diff --git a/appendix/about-cka-candidate.md b/appendix/about-cka-candidate.md
index 4d2ebfab4..c4bdd6b58 100644
--- a/appendix/about-cka-candidate.md
+++ b/appendix/about-cka-candidate.md
@@ -155,7 +155,7 @@ kubectl   get   no   −l   name=hk8s−node−1   −−context=hk8s
 
 该课程的课程大纲：
 
-```text
+```
 Welcome & Introduction
 Container Orchestration
 Kubernetes
@@ -179,7 +179,7 @@ ps： 个人觉得这个课程可以不用学， 直接看文档就行了 。
 
 该课程的课程大纲：
 
-```text
+```
 Kubernetes Fundamentals
 Chapter 1. Course Introduction
 Chapter 2. Basics of Kubernetes
diff --git a/guide/migrating-hadoop-yarn-to-kubernetes.md b/guide/migrating-hadoop-yarn-to-kubernetes.md
index 34b397b81..6f356f21a 100644
--- a/guide/migrating-hadoop-yarn-to-kubernetes.md
+++ b/guide/migrating-hadoop-yarn-to-kubernetes.md
@@ -57,7 +57,7 @@
 
    Hadoop YARN 的 Dockerfile 参考如下配置。
 
-   ```dockerfile
+   ```docker
    FROM my-docker-repo/jdk:7u80
 
    # Add native libs
diff --git a/practice/service-rolling-update.md b/practice/service-rolling-update.md
index 9f2c01b71..6f9390378 100644
--- a/practice/service-rolling-update.md
+++ b/practice/service-rolling-update.md
@@ -67,7 +67,7 @@ func main() {
 
 **创建Dockerfile**
 
-```dockerfile
+```docker
 FROM alpine:3.5
 MAINTAINER Jimmy Song<rootsongjc@gmail.com>
 ADD hellov2 /
diff --git a/usecases/envoy-front-proxy.md b/usecases/envoy-front-proxy.md
index acef19172..46953c98d 100644
--- a/usecases/envoy-front-proxy.md
+++ b/usecases/envoy-front-proxy.md
@@ -92,7 +92,7 @@ networks:
 
 其中 `front-envoy` 是前端（边缘）Envoy 服务，用来做反向代理，它使用的是 `Dockerfile-frontenvoy` 文件来构建镜像的，我们来看下该 `Dockerfile` 的内容。
 
-```dockerfile
+```docker
 FROM envoyproxy/envoy:latest
 
 RUN apt-get update && apt-get -q install -y \
@@ -188,7 +188,7 @@ example_front-envoy_1   /bin/sh -c /usr/local/bin/ ... Up       0.0.0.0:8000->80
 
 ```bash
 $ curl -v localhost:8000/service/1
-* 
+*
 Trying ::1...
 * TCP_NODELAY set
 * Connected to localhost (::1) port 8000 (#0)