diff --git a/eng/common/scripts/get-codeowners.ps1 b/eng/common/scripts/get-codeowners.ps1
index fdf8453acee..dff01ecab60 100644
--- a/eng/common/scripts/get-codeowners.ps1
+++ b/eng/common/scripts/get-codeowners.ps1
@@ -1,49 +1,91 @@
 param (
-  $TargetDirectory, # should be in relative form from root of repo. EG: sdk/servicebus
-  $RootDirectory, # ideally $(Build.SourcesDirectory)
-  $VsoVariable = "" # target devops output variable
+  [string]$TargetDirectory = "", # Code path to code owners. e.g sdk/core/azure-amqp
+  [string]$CodeOwnerFileLocation = "$PSSCriptRoot/../../../.github/CODEOWNERS", # The absolute path of CODEOWNERS file. 
+  [string]$ToolVersion = "1.0.0-dev.20211122.14", # Placeholder. Will update in next PR
+  [string]$ToolPath = (Join-Path ([System.IO.Path]::GetTempPath()) "codeowners-tool-path"), # The place to check the tool existence. Put temp path as default
+  [string]$DevOpsFeed = "https://pkgs.dev.azure.com/azure-sdk/public/_packaging/azure-sdk-for-net/nuget/v3/index.json", # DevOp tool feeds.
+  [string]$VsoVariable = "", # Option of write code owners into devop variable
+  [switch]$IncludeNonUserAliases, # Option to filter out the team alias in code owner list. e.g. Azure/azure-sdk-team
+  [switch]$Test  #Run test functions against the script logic
 )
-$target = $TargetDirectory.ToLower().Trim("/")
-$codeOwnersLocation = Join-Path $RootDirectory -ChildPath ".github/CODEOWNERS"
-$ownedFolders = @{}
 
-if (!(Test-Path $codeOwnersLocation)) {
-  Write-Host "Unable to find CODEOWNERS file in target directory $RootDirectory"
-  exit 1
-}
-
-$codeOwnersContent = Get-Content $codeOwnersLocation
+function Get-CodeOwnersTool()
+{
+  $command = Join-Path $ToolPath "retrieve-codeowners"
+  # Check if the retrieve-codeowners tool exsits or not.
+  if (Get-Command $command -errorAction SilentlyContinue) {
+    return $command
+  }
+  if (!(Test-Path $ToolPath)) {
+    New-Item -ItemType Directory -Path $ToolPath | Out-Null
+  }
+  Write-Host "Installing the retrieve-codeowners tool under $ToolPath... "
+  dotnet tool install --tool-path $ToolPath --add-source $DevOpsFeed --version $ToolVersion "Azure.Sdk.Tools.RetrieveCodeOwners" | Out-Null
 
-foreach ($contentLine in $codeOwnersContent) {
-  if (-not $contentLine.StartsWith("#") -and $contentLine){
-    $splitLine = $contentLine -split "\s+"
-    
-    # CODEOWNERS file can also have labels present after the owner aliases
-    # gh aliases start with @ in codeowners. don't pass on to API calls
-    $ownedFolders[$splitLine[0].ToLower().Trim("/")] = ($splitLine[1..$($splitLine.Length)] `
-      | ? { $_.StartsWith("@") } `
-      | % { return $_.substring(1) }) -join ","
+  # Test to see if the tool properly installed.
+  if (!(Get-Command $command -errorAction SilentlyContinue)) {
+    Write-Error "The retrieve-codeowners tool is not properly installed. Please check your tool path. $ToolPath"
+    return 
   }
+  return $command
 }
 
-$results = $ownedFolders[$target]
-
-if ($results) {
-  Write-Host "Found a folder $results to match $target"
+function Get-CodeOwners ([string]$targetDirectory, [string]$codeOwnerFileLocation, [bool]$includeNonUserAliases = $false)
+{
+  $command = Get-CodeOwnersTool
+  # Filter out the non user alias from code owner list.
+  Write-Host "Testing on $targetDirectory..."
+  if($includeNonUserAliases) {
+    $codeOwnersString = & $command --target-directory $targetDirectory --code-owner-file-path $codeOwnerFileLocation 2>&1
+  }
+  else {
+    $codeOwnersString = & $command --target-directory $targetDirectory --code-owner-file-path $codeOwnerFileLocation --filter-out-non-user-aliases 2>&1
+  }
+  # Failed at the command of fetching code owners.
+  if ($LASTEXITCODE -ne 0) {
+    Write-Host $codeOwnersString
+    return ,@()
+  }
+  
+  $codeOwnersJson = $codeOwnersString | ConvertFrom-Json
+  if (!$codeOwnersJson) {
+    Write-Host "No code owners returned from the path: $targetDirectory"
+    return ,@()
+  }
   
   if ($VsoVariable) {
-    $alreadyPresent = [System.Environment]::GetEnvironmentVariable($VsoVariable)
+    $codeOwners = $codeOwnersJson.Owners -join ","
+    Write-Host "##vso[task.setvariable variable=$VsoVariable;]$codeOwners"
+  }
+
+  return ,@($codeOwnersJson.Owners)
+}
+
+function TestGetCodeOwner([string]$targetDirectory, [string]$codeOwnerFileLocation, [bool]$includeNonUserAliases = $false, [string[]]$expectReturn) {
+  $actualReturn = Get-CodeOwners -targetDirectory $targetDirectory -codeOwnerFileLocation $codeOwnerFileLocation -includeNonUserAliases $IncludeNonUserAliases
 
-    if ($alreadyPresent) { 
-      $results += ",$alreadyPresent"
+  if ($actualReturn.Count -ne $expectReturn.Count) {
+    Write-Error "The length of actual result is not as expected. Expected length: $($expectReturn.Count), Actual length: $($actualReturn.Count)."
+    exit 1
+  }
+  for ($i = 0; $i -lt $expectReturn.Count; $i++) {
+    if ($expectReturn[$i] -ne $actualReturn[$i]) {
+      Write-Error "Expect result $expectReturn[$i] is different than actual result $actualReturn[$i]."
+      exit 1
     }
-    Write-Host "##vso[task.setvariable variable=$VsoVariable;]$results"
   }
+}
 
-  return $results
+if($Test) {
+  $testFile = "$PSSCriptRoot/../../../tools/code-owners-parser/Azure.Sdk.Tools.RetrieveCodeOwners.Tests/CODEOWNERS"
+  TestGetCodeOwner -targetDirectory "sdk" -codeOwnerFileLocation $testFile -includeNonUserAliases $true -expectReturn @("person1", "person2")
+  TestGetCodeOwner -targetDirectory "sdk/noPath" -codeOwnerFileLocation $testFile -includeNonUserAliases $true -expectReturn @("person1", "person2")
+  TestGetCodeOwner -targetDirectory "/sdk/azconfig" -codeOwnerFileLocation $testFile -includeNonUserAliases $true -expectReturn @("person3", "person4")
+  TestGetCodeOwner -targetDirectory "/sdk/azconfig/package" -codeOwnerFileLocation $testFile -includeNonUserAliases $true  $testFile -expectReturn @("person3", "person4")
+  TestGetCodeOwner -targetDirectory "/sd" -codeOwnerFileLocation $testFile -includeNonUserAliases $true  -expectReturn @()
+  TestGetCodeOwner -targetDirectory "/sdk/testUser/" -codeOwnerFileLocation $testFile -expectReturn @("azure-sdk") 
+  exit 0
 }
 else {
-  Write-Host "Unable to match path $target in CODEOWNERS file located at $codeOwnersLocation."
-  Write-Host ($ownedFolders | ConvertTo-Json)
-  return ""
+  return Get-CodeOwners -targetDirectory $TargetDirectory -codeOwnerFileLocation $CodeOwnerFileLocation -includeNonUserAliases $IncludeNonUserAliases
 }
diff --git a/tools/code-owners-parser/Azure.Sdk.Tools.RetrieveCodeOwners.Tests/CODEOWNERS b/tools/code-owners-parser/Azure.Sdk.Tools.RetrieveCodeOwners.Tests/CODEOWNERS
index 8c5af6a868f..d4a23d1bbb1 100644
--- a/tools/code-owners-parser/Azure.Sdk.Tools.RetrieveCodeOwners.Tests/CODEOWNERS
+++ b/tools/code-owners-parser/Azure.Sdk.Tools.RetrieveCodeOwners.Tests/CODEOWNERS
@@ -24,7 +24,10 @@
 # PRLabel: %label
 /sdk/eventhubs/ @person7 @person8
 
+# This is for testing non user aliases case.
+/sdk/testUser/ @azure/azure-sdk-eng  @azure-sdk
+
 # Example for service that does not have the code in the repo but wants issues to be labeled
 # Notice the use of the moniker /<NotInRepo>/
 # ServiceLabel: %label %Service Attention
-/<NotInRepo>/ @person7 @person8
\ No newline at end of file
+/<NotInRepo>/ @person7 @person8
diff --git a/tools/code-owners-parser/ci.yml b/tools/code-owners-parser/ci.yml
index 97068d14b7b..5e23a01c7a0 100644
--- a/tools/code-owners-parser/ci.yml
+++ b/tools/code-owners-parser/ci.yml
@@ -27,9 +27,10 @@ extends:
     ToolDirectory: tools/code-owners-parser
     DotNetCoreVersion: 5.0.301
     TestPostSteps:
-      # This is a simple test for placeholder. Will replace the test with get-codeowners.ps1 in future.
-      - pwsh: |
-          $output = dotnet run --project "tools\code-owners-parser\Azure.Sdk.Tools.RetrieveCodeOwners\Azure.Sdk.Tools.RetrieveCodeOwners.csproj" `
-                      --code-owner-file-path "$(Build.SourcesDirectory)/tools/code-owners-parser/Azure.Sdk.Tools.RetrieveCodeOwners.Tests/CODEOWNERS" --target-directory "sdk"
-          $output | ConvertFrom-Json
-        displayName: Test on code owner tool output
\ No newline at end of file
+      - task: PowerShell@2
+        displayName: Test on code owner tool output
+        inputs:
+          pwsh: true
+          filePath: eng/common/scripts/get-codeowners.ps1
+          arguments: >
+            -Test