diff --git a/BE/src/main/java/com/codesquad/issuetracker/ragdoll/service/IssueService_Ragdoll.java b/BE/src/main/java/com/codesquad/issuetracker/ragdoll/service/IssueService_Ragdoll.java
index b6c1806..e1b77e1 100644
--- a/BE/src/main/java/com/codesquad/issuetracker/ragdoll/service/IssueService_Ragdoll.java
+++ b/BE/src/main/java/com/codesquad/issuetracker/ragdoll/service/IssueService_Ragdoll.java
@@ -162,4 +162,9 @@ private void addAttachedLabelId(Long issueId, Integer labelId) {
     private void deleteAttachedLabelId(Long issueId, Integer labelId) {
         issueDao.deleteAttachedLabelId(issueId, labelId);
     }
+
+    public String updateRelatedMilestone(Long issueId, UpdateMilestoneRequestDto updateMilestoneRequestDto) {
+        issueDao.updateRelatedMilestone(issueId, updateMilestoneRequestDto.getMilestoneId());
+        return ResponseMessages.SUCCESSFULLY_MODIFIED;
+    }
 }