diff --git a/packages/reactivity/__tests__/watch.spec.ts b/packages/reactivity/__tests__/watch.spec.ts
index b3d18e19f71..cb546c12d15 100644
--- a/packages/reactivity/__tests__/watch.spec.ts
+++ b/packages/reactivity/__tests__/watch.spec.ts
@@ -5,6 +5,7 @@ import {
   type WatchOptions,
   type WatchScheduler,
   onWatcherCleanup,
+  reactive,
   ref,
   watch,
 } from '../src'
@@ -209,4 +210,16 @@ describe('watch', () => {
     source.value++
     expect(dummy).toBe(1)
   })
+
+  test('watch callback should not be called when functional source and deep(true)', async () => {
+    const spy = vi.fn()
+    const obj = reactive({ data: { number: 1 } })
+    watch(
+      () => obj.data.number,
+      val => spy(),
+      { deep: true },
+    )
+    obj.data = { number: 1 }
+    expect(spy).toHaveBeenCalledTimes(0)
+  })
 })
diff --git a/packages/reactivity/src/watch.ts b/packages/reactivity/src/watch.ts
index 073bf88b93f..2c6fc9bd439 100644
--- a/packages/reactivity/src/watch.ts
+++ b/packages/reactivity/src/watch.ts
@@ -241,11 +241,15 @@ export function watch(
       // watch(source, cb)
       const newValue = effect.run()
       if (
-        deep ||
         forceTrigger ||
         (isMultiSource
-          ? (newValue as any[]).some((v, i) => hasChanged(v, oldValue[i]))
-          : hasChanged(newValue, oldValue))
+          ? (newValue as any[]).some(
+              (v, i) =>
+                (deep && typeof v === 'object') ||
+                hasChanged(v, (oldValue as any[])[i]),
+            )
+          : (deep && typeof newValue === 'object') ||
+            hasChanged(newValue, oldValue))
       ) {
         // cleanup before running cb again
         if (cleanup) {