diff --git a/packages/runtime-core/src/compat/data.ts b/packages/runtime-core/src/compat/data.ts
index 121c0f9a688..883c64fbbaa 100644
--- a/packages/runtime-core/src/compat/data.ts
+++ b/packages/runtime-core/src/compat/data.ts
@@ -7,18 +7,19 @@ export function deepMergeData(
   to: any,
   from: any,
   instance: ComponentInternalInstance
-) {
+): any {
   for (const key in from) {
     const toVal = to[key]
     const fromVal = from[key]
     if (key in to && isPlainObject(toVal) && isPlainObject(fromVal)) {
       __DEV__ &&
         warnDeprecation(DeprecationTypes.OPTIONS_DATA_MERGE, instance, key)
-      deepMergeData(toVal, fromVal, instance)
+      return deepMergeData(toVal, fromVal, instance)
     } else {
       to[key] = fromVal
     }
   }
+  return to
 }
 
 export function mergeDataOption(to: any, from: any) {