diff --git a/SUMMARY.md b/SUMMARY.md
index 001a7b9..59f0207 100644
--- a/SUMMARY.md
+++ b/SUMMARY.md
@@ -48,6 +48,7 @@
    * [5.5. Database和数据库打交道](ch5-web/ch5-05-database.md)
    * [5.6. Ratelimit 服务流量限制](ch5-web/ch5-06-ratelimit.md)
    * [5.7. Layout大型web项目分层](ch5-web/ch5-07-layout-of-web-project.md)
+   * [5.8. interface 和 table-driven 开发](ch5-web/ch5-08-interface-and-web.md)
    * [5.9. 灰度发布和 A/B test](ch5-web/ch5-09-gated-launch.md)
    * [5.11. Load-balance负载均衡](ch5-web/ch5-11-load-balance.md)
 * [第六章 分布式系统](ch6-cloud/readme.md)
diff --git a/ch5-web/ch5-08-interface-and-web.md b/ch5-web/ch5-08-interface-and-web.md
index a519acb..0c5c2c1 100644
--- a/ch5-web/ch5-08-interface-and-web.md
+++ b/ch5-web/ch5-08-interface-and-web.md
@@ -78,7 +78,7 @@ type OrderCreator interface {
 
 如果我们正在做的是平台系统，需要由平台来定义统一的业务流程和业务规范，那么基于 interface 的抽象就是有意义的。举个例子：
 
-TODO，interface 实现的 uml 图
+![interface-impl](../images/ch6-interface-impl.png)
 
 平台需要服务多条业务线，但数据定义需要统一，所以希望都能走平台定义的流程。作为平台方，我们可以定义一套类似上文的 interface，然后要求接入方的业务必须将这些 interface 都实现。如果 interface 中有其不需要的步骤，那么只要返回 nil，或者忽略就好。
 
diff --git a/images/ch6-interface-impl.plantuml b/images/ch6-interface-impl.plantuml
new file mode 100644
index 0000000..3a80f62
--- /dev/null
+++ b/images/ch6-interface-impl.plantuml
@@ -0,0 +1,34 @@
+@startuml interface-impl
+
+interface OrderCreator
+
+OrderCreator <|-- O2OOrderCreator
+OrderCreator <|-- B2BOrderCreator
+
+interface OrderCreator {
+    ValidateDistrict()
+    ValidateVIPProduct()
+    GetUserInfo()
+    GetProductDesc()
+    DecrementStorage()
+    CreateOrderSnapshot()
+}
+
+class O2OOrderCreator {
+    ValidateDistrict()
+    ValidateVIPProduct()
+    GetUserInfo()
+    GetProductDesc()
+    DecrementStorage()
+    CreateOrderSnapshot()
+}
+
+class B2BOrderCreator {
+    ValidateDistrict()
+    ValidateVIPProduct()
+    GetUserInfo()
+    GetProductDesc()
+    DecrementStorage()
+    CreateOrderSnapshot()
+}
+@enduml
\ No newline at end of file
diff --git a/images/ch6-interface-impl.png b/images/ch6-interface-impl.png
new file mode 100644
index 0000000..8b3a367
Binary files /dev/null and b/images/ch6-interface-impl.png differ