diff --git a/.azure-pipelines/BranchProtectionForPrivateRepo.yml b/.azure-pipelines/BranchProtectionForPrivateRepo.yml
index a826a8ecf271..6bec0d4acad7 100644
--- a/.azure-pipelines/BranchProtectionForPrivateRepo.yml
+++ b/.azure-pipelines/BranchProtectionForPrivateRepo.yml
@@ -1,7 +1,5 @@
 jobs:
   - job: "BranchProtectionForPrivateRepo"
-    pool:
-      vmImage: 'Ubuntu 16.04'
     condition: and(variables['PRIVATE'], eq(variables['System.PullRequest.TargetBranch'], 'main'))
     steps:
     - script: '>&2 echo "the branch is protected"'
diff --git a/.azure-pipelines/ShouldSendPRToMain.yml b/.azure-pipelines/ShouldSendPRToMain.yml
index d139949faeb0..3b934969a841 100644
--- a/.azure-pipelines/ShouldSendPRToMain.yml
+++ b/.azure-pipelines/ShouldSendPRToMain.yml
@@ -1,7 +1,5 @@
 jobs:
   - job: "ShouldSendPRToMain"
-    pool:
-      vmImage: 'Ubuntu 16.04'
     condition: eq(variables['System.PullRequest.TargetBranch'], 'master')
     steps:
     - script: '>&2 echo "##vso[task.logissue type=error]Please edit the pull request to targeting new default branch main"'
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index 96faf6d58c8a..3bbdde1f7b21 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -1,5 +1,8 @@
 name: "Azure OpenAPI"
 
+pool:
+  vmImage: 'Ubuntu-20.04'
+
 trigger:
   branches:
     include:
@@ -19,4 +22,4 @@ variables:
 
 jobs:
 - template: .azure-pipelines/BranchProtectionForPrivateRepo.yml
-- template: .azure-pipelines/ShouldSendPRToMain.yml
\ No newline at end of file
+- template: .azure-pipelines/ShouldSendPRToMain.yml