diff --git a/changelogs/unreleased/add-source-and-merge_request-to-pipeline-webhook.yml b/changelogs/unreleased/add-source-and-merge_request-to-pipeline-webhook.yml
new file mode 100644
index 00000000000..e7300335427
--- /dev/null
+++ b/changelogs/unreleased/add-source-and-merge_request-to-pipeline-webhook.yml
@@ -0,0 +1,5 @@
+---
+title: Add source and merge_request fields to pipeline event webhook
+merge_request: 32373
+author: Bian Jiaping
+type: added
diff --git a/doc/user/project/integrations/webhooks.md b/doc/user/project/integrations/webhooks.md
index 211bbdc2bb9..b508d904606 100644
--- a/doc/user/project/integrations/webhooks.md
+++ b/doc/user/project/integrations/webhooks.md
@@ -1001,6 +1001,7 @@ X-Gitlab-Event: Pipeline Hook
       "tag": false,
       "sha": "bcbb5ec396a2c0f828686f14fac9b80b780504f2",
       "before_sha": "bcbb5ec396a2c0f828686f14fac9b80b780504f2",
+      "source": "merge_request_event",
       "status": "success",
       "stages":[
          "build",
@@ -1016,6 +1017,18 @@ X-Gitlab-Event: Pipeline Hook
           "value": "us-west-1"
         }
       ]
+   },
+    "merge_request": {
+      "id": 1,
+      "iid": 1,
+      "title": "Test",
+      "source_branch": "test",
+      "source_project_id": 1,
+      "target_branch": "master",
+      "target_project_id": 1,
+      "state": "opened",
+      "merge_status": "can_be_merged",
+      "url": "http://192.168.64.1:3005/gitlab-org/gitlab-test/merge_requests/1"
    },
    "user":{
       "name": "Administrator",
diff --git a/lib/gitlab/data_builder/pipeline.rb b/lib/gitlab/data_builder/pipeline.rb
index e1e813849bf..da3d6c47431 100644
--- a/lib/gitlab/data_builder/pipeline.rb
+++ b/lib/gitlab/data_builder/pipeline.rb
@@ -9,6 +9,7 @@ module Gitlab
         {
           object_kind: 'pipeline',
           object_attributes: hook_attrs(pipeline),
+          merge_request: pipeline.merge_request && merge_request_attrs(pipeline.merge_request),
           user: pipeline.user.try(:hook_attrs),
           project: pipeline.project.hook_attrs(backward: false),
           commit: pipeline.commit.try(:hook_attrs),
@@ -23,6 +24,7 @@ module Gitlab
           tag: pipeline.tag,
           sha: pipeline.sha,
           before_sha: pipeline.before_sha,
+          source: pipeline.source,
           status: pipeline.status,
           detailed_status: pipeline.detailed_status(nil).label,
           stages: pipeline.stages_names,
@@ -33,6 +35,21 @@ module Gitlab
         }
       end
 
+      def merge_request_attrs(merge_request)
+        {
+          id: merge_request.id,
+          iid: merge_request.iid,
+          title: merge_request.title,
+          source_branch: merge_request.source_branch,
+          source_project_id: merge_request.source_project_id,
+          target_branch: merge_request.target_branch,
+          target_project_id: merge_request.target_project_id,
+          state: merge_request.state,
+          merge_status: merge_request.merge_status,
+          url: Gitlab::UrlBuilder.build(merge_request)
+        }
+      end
+
       def build_hook_attrs(build)
         {
           id: build.id,
diff --git a/spec/lib/gitlab/data_builder/pipeline_spec.rb b/spec/lib/gitlab/data_builder/pipeline_spec.rb
index 4afb7195b7b..931477d19c2 100644
--- a/spec/lib/gitlab/data_builder/pipeline_spec.rb
+++ b/spec/lib/gitlab/data_builder/pipeline_spec.rb
@@ -28,12 +28,14 @@ describe Gitlab::DataBuilder::Pipeline do
       expect(attributes[:sha]).to eq(pipeline.sha)
       expect(attributes[:tag]).to eq(pipeline.tag)
       expect(attributes[:id]).to eq(pipeline.id)
+      expect(attributes[:source]).to eq(pipeline.source)
       expect(attributes[:status]).to eq(pipeline.status)
       expect(attributes[:detailed_status]).to eq('passed')
       expect(build_data).to be_a(Hash)
       expect(build_data[:id]).to eq(build.id)
       expect(build_data[:status]).to eq(build.status)
       expect(project_data).to eq(project.hook_attrs(backward: false))
+      expect(data[:merge_request]).to be_nil
     end
 
     context 'pipeline without variables' do
@@ -60,6 +62,22 @@ describe Gitlab::DataBuilder::Pipeline do
       it 'returns a source ref' do
         expect(attributes[:ref]).to eq(merge_request.source_branch)
       end
+
+      it 'returns merge request' do
+        merge_request_attrs = data[:merge_request]
+
+        expect(merge_request_attrs).to be_a(Hash)
+        expect(merge_request_attrs[:id]).to eq(merge_request.id)
+        expect(merge_request_attrs[:iid]).to eq(merge_request.iid)
+        expect(merge_request_attrs[:title]).to eq(merge_request.title)
+        expect(merge_request_attrs[:source_branch]).to eq(merge_request.source_branch)
+        expect(merge_request_attrs[:source_project_id]).to eq(merge_request.source_project_id)
+        expect(merge_request_attrs[:target_branch]).to eq(merge_request.target_branch)
+        expect(merge_request_attrs[:target_project_id]).to eq(merge_request.target_project_id)
+        expect(merge_request_attrs[:state]).to eq(merge_request.state)
+        expect(merge_request_attrs[:merge_status]).to eq(merge_request.merge_status)
+        expect(merge_request_attrs[:url]).to eq("http://localhost/#{merge_request.target_project.full_path}/merge_requests/#{merge_request.iid}")
+      end
     end
   end
 end