diff --git a/web/app/components/workflow/nodes/knowledge-base/components/retrieval-setting/reranking-model-selector.spec.tsx b/web/app/components/workflow/nodes/knowledge-base/components/retrieval-setting/reranking-model-selector.spec.tsx
new file mode 100644
index 0000000000..300de76c2e
--- /dev/null
+++ b/web/app/components/workflow/nodes/knowledge-base/components/retrieval-setting/reranking-model-selector.spec.tsx
@@ -0,0 +1,121 @@
+import type {
+  DefaultModel,
+  Model,
+  ModelItem,
+} from '@/app/components/header/account-setting/model-provider-page/declarations'
+import { fireEvent, render, screen } from '@testing-library/react'
+import {
+  ConfigurationMethodEnum,
+  ModelStatusEnum,
+  ModelTypeEnum,
+} from '@/app/components/header/account-setting/model-provider-page/declarations'
+import RerankingModelSelector from './reranking-model-selector'
+
+type MockModelSelectorProps = {
+  defaultModel?: DefaultModel
+  modelList: Model[]
+  onSelect?: (model: DefaultModel) => void
+}
+
+const mockUseModelListAndDefaultModel = vi.hoisted(() => vi.fn())
+
+vi.mock('@/app/components/header/account-setting/model-provider-page/hooks', () => ({
+  useModelListAndDefaultModel: mockUseModelListAndDefaultModel,
+}))
+
+vi.mock('@/app/components/header/account-setting/model-provider-page/model-selector', () => ({
+  default: ({ defaultModel, modelList, onSelect }: MockModelSelectorProps) => (
+    <div>
+      <div data-testid="default-model">
+        {defaultModel ? `${defaultModel.provider}/${defaultModel.model}` : 'no-default-model'}
+      </div>
+      <div data-testid="model-list-count">{modelList.length}</div>
+      <button type="button" onClick={() => onSelect?.({ provider: 'cohere', model: 'rerank-v3' })}>
+        select-model
+      </button>
+    </div>
+  ),
+}))
+
+const createModelItem = (overrides: Partial<ModelItem> = {}): ModelItem => ({
+  model: 'rerank-v3',
+  label: { en_US: 'Rerank V3', zh_Hans: 'Rerank V3' },
+  model_type: ModelTypeEnum.rerank,
+  fetch_from: ConfigurationMethodEnum.predefinedModel,
+  status: ModelStatusEnum.active,
+  model_properties: {},
+  load_balancing_enabled: false,
+  ...overrides,
+})
+
+const createModel = (overrides: Partial<Model> = {}): Model => ({
+  provider: 'cohere',
+  icon_small: {
+    en_US: 'https://example.com/cohere.png',
+    zh_Hans: 'https://example.com/cohere.png',
+  },
+  icon_small_dark: {
+    en_US: 'https://example.com/cohere-dark.png',
+    zh_Hans: 'https://example.com/cohere-dark.png',
+  },
+  label: { en_US: 'Cohere', zh_Hans: 'Cohere' },
+  models: [createModelItem()],
+  status: ModelStatusEnum.active,
+  ...overrides,
+})
+
+describe('RerankingModelSelector', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    mockUseModelListAndDefaultModel.mockReturnValue({
+      modelList: [createModel()],
+      defaultModel: undefined,
+    })
+  })
+
+  // Rendering behavior for mapped rerank model state.
+  describe('Rendering', () => {
+    it('should not pass a default model when reranking model fields are empty strings', () => {
+      render(
+        <RerankingModelSelector
+          rerankingModel={{
+            reranking_provider_name: '',
+            reranking_model_name: '',
+          }}
+        />,
+      )
+
+      expect(screen.getByTestId('default-model')).toHaveTextContent('no-default-model')
+      expect(screen.getByTestId('model-list-count')).toHaveTextContent('1')
+    })
+
+    it('should map reranking model to default model when both fields exist', () => {
+      render(
+        <RerankingModelSelector
+          rerankingModel={{
+            reranking_provider_name: 'cohere',
+            reranking_model_name: 'rerank-v3',
+          }}
+        />,
+      )
+
+      expect(screen.getByTestId('default-model')).toHaveTextContent('cohere/rerank-v3')
+    })
+  })
+
+  // Selection behavior should convert back to workflow reranking model shape.
+  describe('Interactions', () => {
+    it('should map selected model back to reranking model fields', () => {
+      const onRerankingModelChange = vi.fn()
+
+      render(<RerankingModelSelector onRerankingModelChange={onRerankingModelChange} />)
+
+      fireEvent.click(screen.getByRole('button', { name: 'select-model' }))
+
+      expect(onRerankingModelChange).toHaveBeenCalledWith({
+        reranking_provider_name: 'cohere',
+        reranking_model_name: 'rerank-v3',
+      })
+    })
+  })
+})
diff --git a/web/app/components/workflow/nodes/knowledge-base/components/retrieval-setting/reranking-model-selector.tsx b/web/app/components/workflow/nodes/knowledge-base/components/retrieval-setting/reranking-model-selector.tsx
index 3e0bea2b28..7ee18a82e5 100644
--- a/web/app/components/workflow/nodes/knowledge-base/components/retrieval-setting/reranking-model-selector.tsx
+++ b/web/app/components/workflow/nodes/knowledge-base/components/retrieval-setting/reranking-model-selector.tsx
@@ -22,12 +22,12 @@ const RerankingModelSelector = ({
     modelList: rerankModelList,
   } = useModelListAndDefaultModel(ModelTypeEnum.rerank)
   const rerankModel = useMemo(() => {
-    if (!rerankingModel)
+    if (!rerankingModel?.reranking_provider_name || !rerankingModel?.reranking_model_name)
       return undefined
 
     return {
-      providerName: rerankingModel.reranking_provider_name,
-      modelName: rerankingModel.reranking_model_name,
+      provider: rerankingModel.reranking_provider_name,
+      model: rerankingModel.reranking_model_name,
     }
   }, [rerankingModel])
 
@@ -40,7 +40,7 @@ const RerankingModelSelector = ({
 
   return (
     <ModelSelector
-      defaultModel={rerankModel && { provider: rerankModel.providerName, model: rerankModel.modelName }}
+      defaultModel={rerankModel}
       modelList={rerankModelList}
       onSelect={handleRerankingModelChange}
       readonly={readonly}