diff --git a/internal/engine/memory_store.go b/internal/engine/memory_store.go
index bcac28e..721483f 100644
--- a/internal/engine/memory_store.go
+++ b/internal/engine/memory_store.go
@@ -87,11 +87,18 @@ func (ms *MemoryStore) GetCollection(name string) (*Collection, error) {
 	return coll, nil
 }
 
-// Insert 插入文档到内存
+// Insert 插入文档到内存（集合不存在时自动创建）
 func (ms *MemoryStore) Insert(collection string, doc types.Document) error {
 	coll, err := ms.GetCollection(collection)
 	if err != nil {
-		return err
+		// 集合不存在则创建
+		ms.mu.Lock()
+		ms.collections[collection] = &Collection{
+			name:      collection,
+			documents: make(map[string]types.Document),
+		}
+		coll = ms.collections[collection]
+		ms.mu.Unlock()
 	}
 
 	coll.mu.Lock()