diff --git a/document/document.go b/document/document.go
index 66da2cd..f7f4544 100644
--- a/document/document.go
+++ b/document/document.go
@@ -3,19 +3,20 @@ package document
 import (
 	"fmt"
 	"os"
-	"sync"
 	"strings"
-	"go.mongodb.org/mongo-driver/bson/primitive"
-	"go.mongodb.org/mongo-driver/bson"
+	"sync"
+
 	"git.pyer.club/kingecg/godocdb/index"
 	"git.pyer.club/kingecg/godocdb/storage"
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/bson/primitive"
 )
 
 // DocumentStore 管理带命名空间的文档存储
 type DocumentStore struct {
 	storage    *storage.LevelDBStorage
 	indexStore *index.IndexStore // 添加索引存储依赖
-	mu         sync.RWMutex     // 保护并发访问
+	mu         sync.RWMutex      // 保护并发访问
 }
 
 // NewDocumentStore 创建新的文档存储实例
@@ -36,6 +37,9 @@ func NewDocumentStore(path string) (*DocumentStore, error) {
 		storage.Close()
 		return nil, fmt.Errorf("failed to create index store: %v", err)
 	}
+	if errCreate := is.CreateIndex("default_index", index.NonUnique, []string{"_id"}, []index.IndexSortOrder{index.Ascending}); errCreate != nil {
+		return nil, errCreate
+	}
 
 	return &DocumentStore{
 		storage:    storage,
@@ -163,7 +167,7 @@ func getRelatedIndexes(doc map[string]interface{}, coll string, is *index.IndexS
 			return nil, fmt.Errorf("no suitable index found for collection %s", coll)
 		}
 	}
-	
+
 	return related, nil
 }
 
diff --git a/index/index.go b/index/index.go
index 65249e3..02a5b8b 100644
--- a/index/index.go
+++ b/index/index.go
@@ -1,13 +1,14 @@
 package index
 
 import (
+	"bytes"
 	"fmt"
-	"sync"
 	"os"
 	"strings"
-	"bytes"
-	"go.mongodb.org/mongo-driver/bson"
+	"sync"
+
 	"git.pyer.club/kingecg/godocdb/storage"
+	"go.mongodb.org/mongo-driver/bson"
 )
 
 // IndexType 索引类型
@@ -45,6 +46,13 @@ type IndexStore struct {
 // NewIndexStore 创建新的索引存储实例
 func NewIndexStore(path string) (*IndexStore, error) {
 	// 确保目录存在
+	if strings.HasPrefix(path, "/") {
+		path = strings.TrimSuffix(path, "/")
+	}
+	if !strings.HasSuffix(path, "_index") {
+		// add _index suffix to avoid name confilict with document store, do remove this
+		path += "_index"
+	}
 	if err := os.MkdirAll(path, 0755); err != nil {
 		return nil, fmt.Errorf("failed to create storage directory: %v", err)
 	}
diff --git a/index/index_test.go b/index/index_test.go
index 22ecca1..c668311 100644
--- a/index/index_test.go
+++ b/index/index_test.go
@@ -35,7 +35,7 @@ func TestIndexStore(t *testing.T) {
 	}
 
 	if metadata.Name != indexName || metadata.Type != NonUnique {
-		t.Errorf("Metadata mismatch: got %+v want name=%s type=%s", metadata, indexName, NonUnique)
+		t.Errorf("Metadata mismatch: got %+v want name=%s type=%d", metadata, indexName, NonUnique)
 	}
 
 	// 测试删除索引
@@ -78,7 +78,7 @@ func TestCompositeIndex(t *testing.T) {
 	}
 
 	if metadata.Type != NonUnique || len(metadata.KeyFields) != 2 {
-		t.Errorf("Composite index metadata mismatch: got %+v want type=%s fieldsCount=2", metadata, NonUnique)
+		t.Errorf("Composite index metadata mismatch: got %+v want type=%d fieldsCount=2", metadata, NonUnique)
 	}
 }
 
@@ -158,7 +158,7 @@ func TestCompositeIndexSortOrders(t *testing.T) {
 	}
 
 	if metadata.Type != NonUnique || len(metadata.KeyFields) != 2 {
-		t.Errorf("Composite index metadata mismatch: got %+v want type=%s fieldsCount=2", metadata, NonUnique)
+		t.Errorf("Composite index metadata mismatch: got %+v want type=%d fieldsCount=2", metadata, NonUnique)
 	}
 
 	// 验证每个字段的排序方式