diff --git a/spec/object-storage.yaml b/spec/object-storage.yaml
index 562b97a..1edb5e0 100644
--- a/spec/object-storage.yaml
+++ b/spec/object-storage.yaml
@@ -999,6 +999,62 @@ paths:
         500:
           description: server does not response
           content: {}
+  '/api/v1/buckets/{bucket}/metrics/{stat}':
+    get:
+      tags:
+        - Metrics
+      summary: get statistic
+      operationId: getMetrics
+      parameters:
+      - name: bucket
+        in: path
+        required: true
+        schema:
+          type: string
+      - name: stat
+        in: path
+        required: true
+        schema:
+          type: string
+      responses:
+        200:
+          description: successful operation
+          content: 
+            application/json:
+              schema:
+                type: object
+                properties:
+                  status:
+                    type: string
+                  data:
+                    type: object
+                    properties:
+                      bucket:
+                        type: string
+                      metrics:
+                        type: object
+                        properties:
+                          stat:
+                            type: array
+                            items:
+                              oneOf:
+                                - type: number
+                                - type: string
+        400:
+          description: Bad Request
+          content: {}
+        401:
+          description: Missing authentication
+          content: {}
+        404:
+          description: Not Found
+          content: {}
+        409:
+          description: Conflict
+          content: {}
+        500:
+          description: server does not response
+          content: {}
 components:
   schemas:
     Stat: