diff --git a/web/__tests__/workflow-parallel-limit.test.tsx b/web/__tests__/workflow-parallel-limit.test.tsx
new file mode 100644
index 000000000..0843122ab
--- /dev/null
+++ b/web/__tests__/workflow-parallel-limit.test.tsx
@@ -0,0 +1,301 @@
+/**
+ * MAX_PARALLEL_LIMIT Configuration Bug Test
+ *
+ * This test reproduces and verifies the fix for issue #23083:
+ * MAX_PARALLEL_LIMIT environment variable does not take effect in iteration panel
+ */
+
+import { render, screen } from '@testing-library/react'
+import React from 'react'
+
+// Mock environment variables before importing constants
+const originalEnv = process.env.NEXT_PUBLIC_MAX_PARALLEL_LIMIT
+
+// Test with different environment values
+function setupEnvironment(value?: string) {
+  if (value)
+    process.env.NEXT_PUBLIC_MAX_PARALLEL_LIMIT = value
+   else
+    delete process.env.NEXT_PUBLIC_MAX_PARALLEL_LIMIT
+
+  // Clear module cache to force re-evaluation
+  jest.resetModules()
+}
+
+function restoreEnvironment() {
+  if (originalEnv)
+    process.env.NEXT_PUBLIC_MAX_PARALLEL_LIMIT = originalEnv
+   else
+    delete process.env.NEXT_PUBLIC_MAX_PARALLEL_LIMIT
+
+  jest.resetModules()
+}
+
+// Mock i18next with proper implementation
+jest.mock('react-i18next', () => ({
+  useTranslation: () => ({
+    t: (key: string) => {
+      if (key.includes('MaxParallelismTitle')) return 'Max Parallelism'
+      if (key.includes('MaxParallelismDesc')) return 'Maximum number of parallel executions'
+      if (key.includes('parallelMode')) return 'Parallel Mode'
+      if (key.includes('parallelPanelDesc')) return 'Enable parallel execution'
+      if (key.includes('errorResponseMethod')) return 'Error Response Method'
+      return key
+    },
+  }),
+  initReactI18next: {
+    type: '3rdParty',
+    init: jest.fn(),
+  },
+}))
+
+// Mock i18next module completely to prevent initialization issues
+jest.mock('i18next', () => ({
+  use: jest.fn().mockReturnThis(),
+  init: jest.fn().mockReturnThis(),
+  t: jest.fn(key => key),
+  isInitialized: true,
+}))
+
+// Mock the useConfig hook
+jest.mock('@/app/components/workflow/nodes/iteration/use-config', () => ({
+  __esModule: true,
+  default: () => ({
+    inputs: {
+      is_parallel: true,
+      parallel_nums: 5,
+      error_handle_mode: 'terminated',
+    },
+    changeParallel: jest.fn(),
+    changeParallelNums: jest.fn(),
+    changeErrorHandleMode: jest.fn(),
+  }),
+}))
+
+// Mock other components
+jest.mock('@/app/components/workflow/nodes/_base/components/variable/var-reference-picker', () => {
+  return function MockVarReferencePicker() {
+    return <div data-testid="var-reference-picker">VarReferencePicker</div>
+  }
+})
+
+jest.mock('@/app/components/workflow/nodes/_base/components/split', () => {
+  return function MockSplit() {
+    return <div data-testid="split">Split</div>
+  }
+})
+
+jest.mock('@/app/components/workflow/nodes/_base/components/field', () => {
+  return function MockField({ title, children }: { title: string, children: React.ReactNode }) {
+    return (
+      <div data-testid="field">
+        <label>{title}</label>
+        {children}
+      </div>
+    )
+  }
+})
+
+jest.mock('@/app/components/base/switch', () => {
+  return function MockSwitch({ defaultValue }: { defaultValue: boolean }) {
+    return <input type="checkbox" defaultChecked={defaultValue} data-testid="switch" />
+  }
+})
+
+jest.mock('@/app/components/base/select', () => {
+  return function MockSelect() {
+    return <select data-testid="select">Select</select>
+  }
+})
+
+// Use defaultValue to avoid controlled input warnings
+jest.mock('@/app/components/base/slider', () => {
+  return function MockSlider({ value, max, min }: { value: number, max: number, min: number }) {
+    return (
+      <input
+        type="range"
+        defaultValue={value}
+        max={max}
+        min={min}
+        data-testid="slider"
+        data-max={max}
+        data-min={min}
+        readOnly
+      />
+    )
+  }
+})
+
+// Use defaultValue to avoid controlled input warnings
+jest.mock('@/app/components/base/input', () => {
+  return function MockInput({ type, max, min, value }: { type: string, max: number, min: number, value: number }) {
+    return (
+      <input
+        type={type}
+        defaultValue={value}
+        max={max}
+        min={min}
+        data-testid="number-input"
+        data-max={max}
+        data-min={min}
+        readOnly
+      />
+    )
+  }
+})
+
+describe('MAX_PARALLEL_LIMIT Configuration Bug', () => {
+  const mockNodeData = {
+    id: 'test-iteration-node',
+    type: 'iteration' as const,
+    data: {
+      title: 'Test Iteration',
+      desc: 'Test iteration node',
+      iterator_selector: ['test'],
+      output_selector: ['output'],
+      is_parallel: true,
+      parallel_nums: 5,
+      error_handle_mode: 'terminated' as const,
+    },
+  }
+
+  beforeEach(() => {
+    jest.clearAllMocks()
+  })
+
+  afterEach(() => {
+    restoreEnvironment()
+  })
+
+  afterAll(() => {
+    restoreEnvironment()
+  })
+
+  describe('Environment Variable Parsing', () => {
+    it('should parse MAX_PARALLEL_LIMIT from NEXT_PUBLIC_MAX_PARALLEL_LIMIT environment variable', () => {
+      setupEnvironment('25')
+      const { MAX_PARALLEL_LIMIT } = require('@/config')
+      expect(MAX_PARALLEL_LIMIT).toBe(25)
+    })
+
+    it('should fallback to default when environment variable is not set', () => {
+      setupEnvironment() // No environment variable
+      const { MAX_PARALLEL_LIMIT } = require('@/config')
+      expect(MAX_PARALLEL_LIMIT).toBe(10)
+    })
+
+    it('should handle invalid environment variable values', () => {
+      setupEnvironment('invalid')
+      const { MAX_PARALLEL_LIMIT } = require('@/config')
+
+      // Should fall back to default when parsing fails
+      expect(MAX_PARALLEL_LIMIT).toBe(10)
+    })
+
+    it('should handle empty environment variable', () => {
+      setupEnvironment('')
+      const { MAX_PARALLEL_LIMIT } = require('@/config')
+
+      // Should fall back to default when empty
+      expect(MAX_PARALLEL_LIMIT).toBe(10)
+    })
+
+    // Edge cases for boundary values
+    it('should clamp MAX_PARALLEL_LIMIT to MIN when env is 0 or negative', () => {
+      setupEnvironment('0')
+      let { MAX_PARALLEL_LIMIT } = require('@/config')
+      expect(MAX_PARALLEL_LIMIT).toBe(10) // Falls back to default
+
+      setupEnvironment('-5')
+      ;({ MAX_PARALLEL_LIMIT } = require('@/config'))
+      expect(MAX_PARALLEL_LIMIT).toBe(10) // Falls back to default
+    })
+
+    it('should handle float numbers by parseInt behavior', () => {
+      setupEnvironment('12.7')
+      const { MAX_PARALLEL_LIMIT } = require('@/config')
+      // parseInt truncates to integer
+      expect(MAX_PARALLEL_LIMIT).toBe(12)
+    })
+  })
+
+  describe('UI Component Integration (Main Fix Verification)', () => {
+    it('should render iteration panel with environment-configured max value', () => {
+      // Set environment variable to a different value
+      setupEnvironment('30')
+
+      // Import Panel after setting environment
+      const Panel = require('@/app/components/workflow/nodes/iteration/panel').default
+      const { MAX_PARALLEL_LIMIT } = require('@/config')
+
+      render(
+        <Panel
+          id="test-node"
+          data={mockNodeData.data}
+        />,
+      )
+
+      // Behavior-focused assertion: UI max should equal MAX_PARALLEL_LIMIT
+      const numberInput = screen.getByTestId('number-input')
+      expect(numberInput).toHaveAttribute('data-max', String(MAX_PARALLEL_LIMIT))
+
+      const slider = screen.getByTestId('slider')
+      expect(slider).toHaveAttribute('data-max', String(MAX_PARALLEL_LIMIT))
+
+      // Verify the actual values
+      expect(MAX_PARALLEL_LIMIT).toBe(30)
+      expect(numberInput.getAttribute('data-max')).toBe('30')
+      expect(slider.getAttribute('data-max')).toBe('30')
+    })
+
+    it('should maintain UI consistency with different environment values', () => {
+      setupEnvironment('15')
+      const Panel = require('@/app/components/workflow/nodes/iteration/panel').default
+      const { MAX_PARALLEL_LIMIT } = require('@/config')
+
+      render(
+        <Panel
+          id="test-node"
+          data={mockNodeData.data}
+        />,
+      )
+
+      // Both input and slider should use the same max value from MAX_PARALLEL_LIMIT
+      const numberInput = screen.getByTestId('number-input')
+      const slider = screen.getByTestId('slider')
+
+      expect(numberInput.getAttribute('data-max')).toBe(slider.getAttribute('data-max'))
+      expect(numberInput.getAttribute('data-max')).toBe(String(MAX_PARALLEL_LIMIT))
+    })
+  })
+
+  describe('Legacy Constant Verification (For Transition Period)', () => {
+    // Marked as transition/deprecation tests
+    it('should maintain MAX_ITERATION_PARALLEL_NUM for backward compatibility', () => {
+      const { MAX_ITERATION_PARALLEL_NUM } = require('@/app/components/workflow/constants')
+      expect(typeof MAX_ITERATION_PARALLEL_NUM).toBe('number')
+      expect(MAX_ITERATION_PARALLEL_NUM).toBe(10) // Hardcoded legacy value
+    })
+
+    it('should demonstrate MAX_PARALLEL_LIMIT vs legacy constant difference', () => {
+      setupEnvironment('50')
+      const { MAX_PARALLEL_LIMIT } = require('@/config')
+      const { MAX_ITERATION_PARALLEL_NUM } = require('@/app/components/workflow/constants')
+
+      // MAX_PARALLEL_LIMIT is configurable, MAX_ITERATION_PARALLEL_NUM is not
+      expect(MAX_PARALLEL_LIMIT).toBe(50)
+      expect(MAX_ITERATION_PARALLEL_NUM).toBe(10)
+      expect(MAX_PARALLEL_LIMIT).not.toBe(MAX_ITERATION_PARALLEL_NUM)
+    })
+  })
+
+  describe('Constants Validation', () => {
+    it('should validate that required constants exist and have correct types', () => {
+      const { MAX_PARALLEL_LIMIT } = require('@/config')
+      const { MIN_ITERATION_PARALLEL_NUM } = require('@/app/components/workflow/constants')
+      expect(typeof MAX_PARALLEL_LIMIT).toBe('number')
+      expect(typeof MIN_ITERATION_PARALLEL_NUM).toBe('number')
+      expect(MAX_PARALLEL_LIMIT).toBeGreaterThanOrEqual(MIN_ITERATION_PARALLEL_NUM)
+    })
+  })
+})
diff --git a/web/app/components/workflow/constants.ts b/web/app/components/workflow/constants.ts
index 0ef4dc9de..5bf053e2c 100644
--- a/web/app/components/workflow/constants.ts
+++ b/web/app/components/workflow/constants.ts
@@ -437,14 +437,6 @@ export const NODE_LAYOUT_HORIZONTAL_PADDING = 60
 export const NODE_LAYOUT_VERTICAL_PADDING = 60
 export const NODE_LAYOUT_MIN_DISTANCE = 100
 
-let maxParallelLimit = 10
-
-if (process.env.NEXT_PUBLIC_MAX_PARALLEL_LIMIT && process.env.NEXT_PUBLIC_MAX_PARALLEL_LIMIT !== '')
-  maxParallelLimit = Number.parseInt(process.env.NEXT_PUBLIC_MAX_PARALLEL_LIMIT)
-else if (globalThis.document?.body?.getAttribute('data-public-max-parallel-limit') && globalThis.document.body.getAttribute('data-public-max-parallel-limit') !== '')
-  maxParallelLimit = Number.parseInt(globalThis.document.body.getAttribute('data-public-max-parallel-limit') as string)
-
-export const PARALLEL_LIMIT = maxParallelLimit
 export const PARALLEL_DEPTH_LIMIT = 3
 
 export const RETRIEVAL_OUTPUT_STRUCT = `{
diff --git a/web/app/components/workflow/hooks/use-workflow.ts b/web/app/components/workflow/hooks/use-workflow.ts
index 8bc9d3436..f9120f45b 100644
--- a/web/app/components/workflow/hooks/use-workflow.ts
+++ b/web/app/components/workflow/hooks/use-workflow.ts
@@ -30,7 +30,6 @@ import {
 } from '../utils'
 import {
   PARALLEL_DEPTH_LIMIT,
-  PARALLEL_LIMIT,
   SUPPORT_OUTPUT_VARS_NODE,
 } from '../constants'
 import { CUSTOM_NOTE_NODE } from '../note-node/constants'
@@ -48,6 +47,7 @@ import { CUSTOM_ITERATION_START_NODE } from '@/app/components/workflow/nodes/ite
 import { CUSTOM_LOOP_START_NODE } from '@/app/components/workflow/nodes/loop-start/constants'
 import { basePath } from '@/utils/var'
 import { canFindTool } from '@/utils'
+import { MAX_PARALLEL_LIMIT } from '@/config'
 
 export const useIsChatMode = () => {
   const appDetail = useAppStore(s => s.appDetail)
@@ -270,8 +270,6 @@ export const useWorkflow = () => {
       })
       setNodes(newNodes)
     }
-
-    // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [store])
 
   const isVarUsedInNodes = useCallback((varSelector: ValueSelector) => {
@@ -310,9 +308,9 @@ export const useWorkflow = () => {
       edges,
     } = store.getState()
     const connectedEdges = edges.filter(edge => edge.source === nodeId && edge.sourceHandle === nodeHandle)
-    if (connectedEdges.length > PARALLEL_LIMIT - 1) {
+    if (connectedEdges.length > MAX_PARALLEL_LIMIT - 1) {
       const { setShowTips } = workflowStore.getState()
-      setShowTips(t('workflow.common.parallelTip.limit', { num: PARALLEL_LIMIT }))
+      setShowTips(t('workflow.common.parallelTip.limit', { num: MAX_PARALLEL_LIMIT }))
       return false
     }
 
diff --git a/web/app/components/workflow/nodes/iteration/panel.tsx b/web/app/components/workflow/nodes/iteration/panel.tsx
index 4b529f078..23e93b0dd 100644
--- a/web/app/components/workflow/nodes/iteration/panel.tsx
+++ b/web/app/components/workflow/nodes/iteration/panel.tsx
@@ -3,7 +3,7 @@ import React from 'react'
 import { useTranslation } from 'react-i18next'
 import VarReferencePicker from '../_base/components/variable/var-reference-picker'
 import Split from '../_base/components/split'
-import { MAX_ITERATION_PARALLEL_NUM, MIN_ITERATION_PARALLEL_NUM } from '../../constants'
+import { MIN_ITERATION_PARALLEL_NUM } from '../../constants'
 import type { IterationNodeType } from './types'
 import useConfig from './use-config'
 import { ErrorHandleMode, type NodePanelProps } from '@/app/components/workflow/types'
@@ -12,6 +12,7 @@ import Switch from '@/app/components/base/switch'
 import Select from '@/app/components/base/select'
 import Slider from '@/app/components/base/slider'
 import Input from '@/app/components/base/input'
+import { MAX_PARALLEL_LIMIT } from '@/config'
 
 const i18nPrefix = 'workflow.nodes.iteration'
 
@@ -96,11 +97,11 @@ const Panel: FC<NodePanelProps<IterationNodeType>> = ({
         inputs.is_parallel && (<div className='px-4 pb-2'>
           <Field title={t(`${i18nPrefix}.MaxParallelismTitle`)} isSubTitle tooltip={<div className='w-[230px]'>{t(`${i18nPrefix}.MaxParallelismDesc`)}</div>}>
             <div className='row flex'>
-              <Input type='number' wrapperClassName='w-18 mr-4 ' max={MAX_ITERATION_PARALLEL_NUM} min={MIN_ITERATION_PARALLEL_NUM} value={inputs.parallel_nums} onChange={(e) => { changeParallelNums(Number(e.target.value)) }} />
+              <Input type='number' wrapperClassName='w-18 mr-4 ' max={MAX_PARALLEL_LIMIT} min={MIN_ITERATION_PARALLEL_NUM} value={inputs.parallel_nums} onChange={(e) => { changeParallelNums(Number(e.target.value)) }} />
               <Slider
                 value={inputs.parallel_nums}
                 onChange={changeParallelNums}
-                max={MAX_ITERATION_PARALLEL_NUM}
+                max={MAX_PARALLEL_LIMIT}
                 min={MIN_ITERATION_PARALLEL_NUM}
                 className=' mt-4 flex-1 shrink-0'
               />
diff --git a/web/config/index.ts b/web/config/index.ts
index 667723aaa..4a8b07d6e 100644
--- a/web/config/index.ts
+++ b/web/config/index.ts
@@ -13,12 +13,18 @@ const getBooleanConfig = (envVar: string | undefined, dataAttrKey: DatasetAttr,
 }
 
 const getNumberConfig = (envVar: string | undefined, dataAttrKey: DatasetAttr, defaultValue: number) => {
-  if (envVar)
-    return Number.parseInt(envVar)
+  if (envVar) {
+    const parsed = Number.parseInt(envVar)
+    if (!Number.isNaN(parsed) && parsed > 0)
+      return parsed
+  }
 
   const attrValue = globalThis.document?.body?.getAttribute(dataAttrKey)
-  if (attrValue)
-    return Number.parseInt(attrValue)
+  if (attrValue) {
+    const parsed = Number.parseInt(attrValue)
+    if (!Number.isNaN(parsed) && parsed > 0)
+      return parsed
+  }
   return defaultValue
 }
 
@@ -265,6 +271,7 @@ export const FULL_DOC_PREVIEW_LENGTH = 50
 export const JSON_SCHEMA_MAX_DEPTH = 10
 
 export const MAX_TOOLS_NUM = getNumberConfig(process.env.NEXT_PUBLIC_MAX_TOOLS_NUM, DatasetAttr.DATA_PUBLIC_MAX_TOOLS_NUM, 10)
+export const MAX_PARALLEL_LIMIT = getNumberConfig(process.env.NEXT_PUBLIC_MAX_PARALLEL_LIMIT, DatasetAttr.DATA_PUBLIC_MAX_PARALLEL_LIMIT, 10)
 export const TEXT_GENERATION_TIMEOUT_MS = getNumberConfig(process.env.NEXT_PUBLIC_TEXT_GENERATION_TIMEOUT_MS, DatasetAttr.DATA_PUBLIC_TEXT_GENERATION_TIMEOUT_MS, 60000)
 export const LOOP_NODE_MAX_COUNT = getNumberConfig(process.env.NEXT_PUBLIC_LOOP_NODE_MAX_COUNT, DatasetAttr.DATA_PUBLIC_LOOP_NODE_MAX_COUNT, 100)
 export const MAX_ITERATIONS_NUM = getNumberConfig(process.env.NEXT_PUBLIC_MAX_ITERATIONS_NUM, DatasetAttr.DATA_PUBLIC_MAX_ITERATIONS_NUM, 99)