diff --git a/backend/plugins/bitbucket/tasks/pr_commit_collector.go b/backend/plugins/bitbucket/tasks/pr_commit_collector.go
index d4315d24961..2f47d68bb02 100644
--- a/backend/plugins/bitbucket/tasks/pr_commit_collector.go
+++ b/backend/plugins/bitbucket/tasks/pr_commit_collector.go
@@ -55,19 +55,8 @@ func CollectApiPullRequestCommits(taskCtx plugin.SubTaskContext) errors.Error {
 		Input:                 iterator,
 		UrlTemplate:           "repositories/{{ .Params.FullName }}/pullrequests/{{ .Input.BitbucketId }}/commits",
 		GetNextPageCustomData: GetNextPageCustomData,
-		Query: func(reqData *helper.RequestData) (url.Values, errors.Error) {
-			query := url.Values{}
-			query.Set("state", "all")
-			query.Set("pagelen", fmt.Sprintf("%v", reqData.Pager.Size))
-			query.Set("sort", "created_on")
-			query.Set("fields", "values.hash,values.date,values.message,values.author.raw,values.author.user.username,values.author.user.account_id,values.links.self")
-
-			if reqData.CustomData != nil {
-				query.Set("page", reqData.CustomData.(string))
-			}
-			return query, nil
-		},
-		ResponseParser: GetRawMessageFromResponse,
+		Query:                 getPrCommitsQuery,
+		ResponseParser:        GetRawMessageFromResponse,
 		// some pr have no commit
 		// such as: https://bitbucket.org/amdatulabs/amdatu-kubernetes-deployer/pull-requests/21
 		AfterResponse: ignoreHTTPStatus404,
@@ -78,3 +67,19 @@ func CollectApiPullRequestCommits(taskCtx plugin.SubTaskContext) errors.Error {
 
 	return collectorWithState.Execute()
 }
+
+// getPrCommitsQuery builds the query for one page of a pull request's commits.
+// The fields list must include `next`: Bitbucket only returns the fields that are
+// listed, and GetNextPageCustomData reads the next page from `next`.
+func getPrCommitsQuery(reqData *helper.RequestData) (url.Values, errors.Error) {
+	query := url.Values{}
+	query.Set("state", "all")
+	query.Set("pagelen", fmt.Sprintf("%v", reqData.Pager.Size))
+	query.Set("sort", "created_on")
+	query.Set("fields", "values.hash,values.date,values.message,values.author.raw,values.author.user.username,values.author.user.account_id,values.links.self,next")
+
+	if reqData.CustomData != nil {
+		query.Set("page", reqData.CustomData.(string))
+	}
+	return query, nil
+}
diff --git a/backend/plugins/bitbucket/tasks/pr_commit_collector_test.go b/backend/plugins/bitbucket/tasks/pr_commit_collector_test.go
new file mode 100644
index 00000000000..fabfdab2b54
--- /dev/null
+++ b/backend/plugins/bitbucket/tasks/pr_commit_collector_test.go
@@ -0,0 +1,71 @@
+/*
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements.  See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License.  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package tasks
+
+import (
+	"bytes"
+	"encoding/json"
+	"io"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/apache/devlake/helpers/pluginhelper/api"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// keepTopLevelFields mimics Bitbucket's partial response: only the top-level
+// keys named in `fields` (e.g. `values` for `values.hash`) are returned.
+func keepTopLevelFields(t *testing.T, full string, fields string) []byte {
+	var body map[string]json.RawMessage
+	require.NoError(t, json.Unmarshal([]byte(full), &body))
+	keep := map[string]bool{}
+	for _, f := range strings.Split(fields, ",") {
+		keep[strings.SplitN(f, ".", 2)[0]] = true
+	}
+	for k := range body {
+		if !keep[k] {
+			delete(body, k)
+		}
+	}
+	filtered, err := json.Marshal(body)
+	require.NoError(t, err)
+	return filtered
+}
+
+func TestGetPrCommitsQueryFollowsNextPage(t *testing.T) {
+	query, err := getPrCommitsQuery(&api.RequestData{Pager: &api.Pager{Page: 1, Size: 100}})
+	require.NoError(t, err)
+	assert.Equal(t, "100", query.Get("pagelen"))
+	assert.Empty(t, query.Get("page"))
+
+	full := `{
+		"values": [{"hash": "a50685cd98297edd1b248049f199396434726c97"}],
+		"pagelen": 100,
+		"next": "https://api.bitbucket.org/2.0/repositories/ws/repo/pullrequests/1/commits?pagelen=100&page=E8Ux"
+	}`
+	res := &http.Response{Body: io.NopCloser(bytes.NewReader(keepTopLevelFields(t, full, query.Get("fields"))))}
+	next, err := GetNextPageCustomData(nil, res)
+	require.NoError(t, err)
+	assert.Equal(t, "E8Ux", next)
+
+	query, err = getPrCommitsQuery(&api.RequestData{Pager: &api.Pager{Page: 2, Size: 100}, CustomData: next})
+	require.NoError(t, err)
+	assert.Equal(t, "E8Ux", query.Get("page"))
+}