diff --git a/server/skillhub-app/src/main/resources/messages.properties b/server/skillhub-app/src/main/resources/messages.properties
index 1fea61ca..68540961 100644
--- a/server/skillhub-app/src/main/resources/messages.properties
+++ b/server/skillhub-app/src/main/resources/messages.properties
@@ -167,3 +167,4 @@ validation.auth.password.reset.email.invalid=Email format is invalid
 validation.auth.password.reset.code.notBlank=Verification code cannot be blank
 validation.auth.password.reset.code.invalid=Verification code must be 6 digits
 validation.auth.password.reset.newPassword.notBlank=New password cannot be blank
+promotion.target_skill_conflict=The target global skill "{0}" already exists
diff --git a/server/skillhub-app/src/main/resources/messages_zh.properties b/server/skillhub-app/src/main/resources/messages_zh.properties
index 05bd0905..c1f782f0 100644
--- a/server/skillhub-app/src/main/resources/messages_zh.properties
+++ b/server/skillhub-app/src/main/resources/messages_zh.properties
@@ -167,3 +167,4 @@ validation.auth.password.reset.email.invalid=邮箱格式不正确
 validation.auth.password.reset.code.notBlank=验证码不能为空
 validation.auth.password.reset.code.invalid=验证码必须为 6 位数字
 validation.auth.password.reset.newPassword.notBlank=新密码不能为空
+promotion.target_skill_conflict=目标全局技能“{0}”已存在
diff --git a/server/skillhub-domain/src/main/java/com/iflytek/skillhub/domain/review/PromotionService.java b/server/skillhub-domain/src/main/java/com/iflytek/skillhub/domain/review/PromotionService.java
index eb533b8a..67d70c0f 100644
--- a/server/skillhub-domain/src/main/java/com/iflytek/skillhub/domain/review/PromotionService.java
+++ b/server/skillhub-domain/src/main/java/com/iflytek/skillhub/domain/review/PromotionService.java
@@ -16,6 +16,7 @@ import com.iflytek.skillhub.domain.shared.exception.DomainNotFoundException;
 import com.iflytek.skillhub.domain.skill.*;
 import jakarta.persistence.EntityManager;
 import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -207,6 +208,8 @@ public class PromotionService {
         SkillVersion sourceVersion = skillVersionRepository.findById(approvedRequest.getSourceVersionId())
                 .orElseThrow(() -> new DomainNotFoundException("skill_version.not_found", approvedRequest.getSourceVersionId()));
 
+        assertTargetSkillNotExists(approvedRequest, sourceSkill);
+
         // Create new skill in global namespace
         Skill newSkill = new Skill(approvedRequest.getTargetNamespaceId(), sourceSkill.getSlug(),
                 sourceSkill.getOwnerId(), SkillVisibility.PUBLIC);
@@ -215,7 +218,11 @@ public class PromotionService {
         newSkill.setSourceSkillId(sourceSkill.getId());
         newSkill.setCreatedBy(reviewerId);
         newSkill.setUpdatedBy(reviewerId);
-        newSkill = skillRepository.save(newSkill);
+        try {
+            newSkill = skillRepository.save(newSkill);
+        } catch (DataIntegrityViolationException ex) {
+            throw duplicateTargetSkillConflict(sourceSkill.getSlug(), ex);
+        }
 
         // Create new version copying metadata from source
         SkillVersion newVersion = new SkillVersion(newSkill.getId(), sourceVersion.getVersion(),
@@ -264,6 +271,24 @@ public class PromotionService {
         return savedRequest;
     }
 
+    private void assertTargetSkillNotExists(PromotionRequest approvedRequest, Skill sourceSkill) {
+        skillRepository.findByNamespaceIdAndSlugAndOwnerId(
+                approvedRequest.getTargetNamespaceId(),
+                sourceSkill.getSlug(),
+                sourceSkill.getOwnerId()
+        ).ifPresent(existing -> {
+            throw duplicateTargetSkillConflict(sourceSkill.getSlug(), null);
+        });
+    }
+
+    private DomainBadRequestException duplicateTargetSkillConflict(String slug, Exception cause) {
+        DomainBadRequestException ex = new DomainBadRequestException("promotion.target_skill_conflict", slug);
+        if (cause != null) {
+            ex.initCause(cause);
+        }
+        return ex;
+    }
+
     /**
      * Rejects a pending promotion request without changing the source skill.
      */
diff --git a/server/skillhub-domain/src/test/java/com/iflytek/skillhub/domain/review/PromotionServiceTest.java b/server/skillhub-domain/src/test/java/com/iflytek/skillhub/domain/review/PromotionServiceTest.java
index ea00a449..0df9342d 100644
--- a/server/skillhub-domain/src/test/java/com/iflytek/skillhub/domain/review/PromotionServiceTest.java
+++ b/server/skillhub-domain/src/test/java/com/iflytek/skillhub/domain/review/PromotionServiceTest.java
@@ -19,6 +19,7 @@ import org.mockito.ArgumentCaptor;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
 import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.dao.DataIntegrityViolationException;
 
 import java.time.Clock;
 import java.time.Instant;
@@ -511,6 +512,28 @@ class PromotionServiceTest {
                     () -> promotionService.approvePromotion(PROMOTION_ID, REVIEWER_ID, "ok", Set.of("SKILL_ADMIN")));
         }
 
+        @Test
+        void shouldTranslateDuplicateTargetSkillIntoBadRequest() {
+            PromotionRequest pr = createPendingPromotion();
+            Skill sourceSkill = createSourceSkill();
+            SkillVersion sourceVersion = createPublishedVersion();
+
+            when(promotionRequestRepository.findById(PROMOTION_ID)).thenReturn(Optional.of(pr));
+            when(permissionChecker.canReviewPromotion(pr, REVIEWER_ID, Set.of("SKILL_ADMIN"))).thenReturn(true);
+            when(promotionRequestRepository.updateStatusWithVersion(
+                    PROMOTION_ID, ReviewTaskStatus.APPROVED, REVIEWER_ID, "ok", null, pr.getVersion()))
+                    .thenReturn(1);
+            when(skillRepository.findById(SOURCE_SKILL_ID)).thenReturn(Optional.of(sourceSkill));
+            when(skillVersionRepository.findById(SOURCE_VERSION_ID)).thenReturn(Optional.of(sourceVersion));
+            when(skillRepository.save(any(Skill.class)))
+                    .thenThrow(new DataIntegrityViolationException("duplicate key value violates unique constraint"));
+
+            DomainBadRequestException ex = assertThrows(DomainBadRequestException.class,
+                    () -> promotionService.approvePromotion(PROMOTION_ID, REVIEWER_ID, "ok", Set.of("SKILL_ADMIN")));
+
+            assertEquals("promotion.target_skill_conflict", ex.messageCode());
+        }
+
         @Test
         void shouldCopyDisplayNameAndSummaryToNewSkill() {
             PromotionRequest pr = createPendingPromotion();