diff --git a/.changeset/strong-worms-watch.md b/.changeset/strong-worms-watch.md
new file mode 100644
index 0000000..ffeadd1
--- /dev/null
+++ b/.changeset/strong-worms-watch.md
@@ -0,0 +1,5 @@
+---
+"@alova/wormhole": patch
+---
+
+handle array default items in union and avoid TypeError
diff --git a/packages/wormhole/src/core/loader/astLoader/normalize/rules/convertTypeArray.ts b/packages/wormhole/src/core/loader/astLoader/normalize/rules/convertTypeArray.ts
index 079a9fb..a3d3f84 100644
--- a/packages/wormhole/src/core/loader/astLoader/normalize/rules/convertTypeArray.ts
+++ b/packages/wormhole/src/core/loader/astLoader/normalize/rules/convertTypeArray.ts
@@ -17,6 +17,13 @@ export const TYPE_SPECIFIC_KEYWORDS = {
   array: ['items', 'minItems', 'maxItems', 'uniqueItems'],
   object: ['properties', 'additionalProperties', 'required', 'minProperties', 'maxProperties'],
 }
+export const TYPE_REQUIRE_KEYWORDS: Record<string, Array<[string, any]>> = {
+  string: [],
+  number: [],
+  integer: [],
+  array: [['items', { type: 'any' }]],
+  object: [],
+}
 
 export function assignTypeSpecificKeywords(
   branch: SchemaObject,
@@ -24,6 +31,7 @@ export function assignTypeSpecificKeywords(
   typeSpecificKeywords: Record<string, any>,
 ) {
   const keywords = TYPE_SPECIFIC_KEYWORDS[type as keyof typeof TYPE_SPECIFIC_KEYWORDS]
+  const requireKeywords = TYPE_REQUIRE_KEYWORDS[type as keyof typeof TYPE_REQUIRE_KEYWORDS]
   if (!keywords) {
     return
   }
@@ -32,6 +40,11 @@ export function assignTypeSpecificKeywords(
       (branch as any)[key] = typeSpecificKeywords[key]
     }
   })
+  requireKeywords.forEach(([key, value]) => {
+    if (!(key in typeSpecificKeywords)) {
+      (branch as any)[key] = value
+    }
+  })
 }
 
 export default function convertTypeArray(schema: SchemaObject): SchemaObject | void {
diff --git a/packages/wormhole/test/generates/array.test.ts b/packages/wormhole/test/generates/array.test.ts
index 3e42e6a..7df6c31 100644
--- a/packages/wormhole/test/generates/array.test.ts
+++ b/packages/wormhole/test/generates/array.test.ts
@@ -108,7 +108,7 @@ describe('array Type Generator', () => {
       comment: ``,
       type: 'type',
       code: `Array<{
-        value?:string 
+        value?:string
       }>`,
     })
     expect(result).toEqual(expectResult)
@@ -167,4 +167,22 @@ describe('array Type Generator', () => {
     })
     expect(result).toEqual(expectResult)
   })
+
+  it('should generate array type with ANY default', async () => {
+    const ast: TArray = {
+      type: ASTType.ARRAY,
+      keyName: 'AnyArray',
+      params: {
+        type: ASTType.ANY,
+      },
+    }
+    const result = await normalizeGeneratorResult(arrayTypeGenerator(ast, defaultCtx))
+    const expectResult = await normalizeGeneratorResult({
+      name: 'AnyArray',
+      comment: ``,
+      type: 'type',
+      code: `any[]`,
+    })
+    expect(result).toEqual(expectResult)
+  })
 })
diff --git a/packages/wormhole/test/generates/group.test.ts b/packages/wormhole/test/generates/group.test.ts
index dd2bcdd..f0f8e73 100644
--- a/packages/wormhole/test/generates/group.test.ts
+++ b/packages/wormhole/test/generates/group.test.ts
@@ -35,7 +35,7 @@ describe('group Type Generator', () => {
       name: 'Status',
       comment: `
       /**
-       * Status type 
+       * Status type
        */`,
       type: 'type',
       code: 'string | number',
@@ -83,10 +83,10 @@ describe('group Type Generator', () => {
        * User with role
        */`,
       type: 'type',
-      code: `{ 
-        name?:string 
-      } & { 
-        role?:string 
+      code: `{
+        name?:string
+      } & {
+        role?:string
       }`,
     })
     expect(result).toEqual(expectResult)
@@ -145,12 +145,12 @@ describe('group Type Generator', () => {
       name: 'ComplexType',
       comment: '',
       type: 'type',
-      code: `{ 
-        id?:number 
+      code: `{
+        id?:number
       } & {
-        name?:string 
+        name?:string
       } | {
-        code?:string 
+        code?:string
       }`,
     })
     expect(result).toEqual(expectResult)
@@ -196,12 +196,38 @@ describe('group Type Generator', () => {
       name: 'DeepTest',
       comment: '',
       type: 'type',
-      code: `{ 
-        value?:string 
+      code: `{
+        value?:string
       } | {
-        value?:number 
+        value?:number
       }`,
     })
     expect(result).toEqual(expectResult)
   })
+
+  it('should generate union including array(any) and null (fix #140)', async () => {
+    const ast: TUnion = {
+      type: ASTType.UNION,
+      keyName: 'MaybeArray',
+      params: [
+        {
+          type: ASTType.ARRAY,
+          params: {
+            type: ASTType.ANY,
+          },
+        },
+        {
+          type: ASTType.NULL,
+        },
+      ],
+    }
+    const result = await normalizeGeneratorResult(groupTypeGenerator(ast, defaultCtx))
+    const expectResult = await normalizeGeneratorResult({
+      name: 'MaybeArray',
+      comment: '',
+      type: 'type',
+      code: 'any[] | null',
+    })
+    expect(result).toEqual(expectResult)
+  })
 })
diff --git a/packages/wormhole/test/normalize.spec.ts b/packages/wormhole/test/normalize.spec.ts
index c80aefd..8e81206 100644
--- a/packages/wormhole/test/normalize.spec.ts
+++ b/packages/wormhole/test/normalize.spec.ts
@@ -164,6 +164,46 @@ describe('schema Normalizer', () => {
       expect(stringBranch.minLength).toBe(5)
       expect((stringBranch as ArraySchemaObject).items).toBeUndefined()
     })
+
+    it('should assign default items for array branch when items missing', () => {
+      const schema: SchemaObject = {
+        type: ['array', 'string'],
+        minLength: 5,
+        title: 'Test',
+      }
+
+      const result = normalizer.normalize(schema) as SchemaObject
+      expect(result.anyOf).toBeDefined()
+      expect(result.anyOf).toHaveLength(2)
+
+      const arrayBranch = result.anyOf![0] as ArraySchemaObject
+      const stringBranch = result.anyOf![1] as SchemaObject
+
+      expect(arrayBranch.type).toBe('array')
+      expect(arrayBranch.items).toBeDefined()
+      expect((arrayBranch.items as SchemaObject).type).toBeDefined()
+      expect(stringBranch.type).toBe('string')
+      expect(stringBranch.minLength).toBe(5)
+    })
+
+    it('should handle array | null union by injecting default items into array branch (fix #140)', () => {
+      const schema: SchemaObject = {
+        type: ['array', 'null'] as any,
+        title: 'Issue 140',
+      }
+      const result = normalizer.normalize(schema) as SchemaObject
+      expect(result.type).toBeUndefined()
+      expect(result.anyOf).toBeDefined()
+      expect(result.anyOf).toHaveLength(2)
+
+      const arrayBranch = result.anyOf![0] as ArraySchemaObject
+      const nullBranch = result.anyOf![1] as SchemaObject
+
+      expect(arrayBranch.type).toBe('array')
+      expect(arrayBranch.items).toBeDefined()
+      expect((arrayBranch.items as SchemaObject).type).toBeDefined()
+      expect(nullBranch.type).toBe('null')
+    })
   })
 
   describe('mergeAnyOf rule', () => {