diff --git a/internal/web/service/node.go b/internal/web/service/node.go
index bafccd23c..d1e14d243 100644
--- a/internal/web/service/node.go
+++ b/internal/web/service/node.go
@@ -24,6 +24,8 @@ import (
 	"github.com/mhsanaei/3x-ui/v3/internal/util/netsafe"
 	"github.com/mhsanaei/3x-ui/v3/internal/web/runtime"
 	"github.com/mhsanaei/3x-ui/v3/internal/xray"
+
+	"gorm.io/gorm"
 )
 
 type HeartbeatPatch struct {
@@ -439,6 +441,17 @@ func FilterNodeSnapshot(n *model.Node, snap *runtime.TrafficSnapshot) {
 
 func (s *NodeService) Delete(id int) error {
 	db := database.GetDB()
+	// Refuse to delete a node that still owns inbounds: dropping the node row
+	// while inbounds keep its node_id leaves orphaned, dangling references that
+	// confuse node sync, subscriptions and cleanup. The operator must detach or
+	// remove those inbounds first. (DB-002)
+	var attached int64
+	if err := db.Model(&model.Inbound{}).Where("node_id = ?", id).Count(&attached).Error; err != nil {
+		return err
+	}
+	if attached > 0 {
+		return common.NewError(fmt.Sprintf("cannot delete node: %d inbound(s) still attached to it; detach or delete them first", attached))
+	}
 	// Capture the node's guid before deleting the row so we can drop its per-node
 	// IP attribution (NodeClientIp is keyed by guid, not node id).
 	var guid string
@@ -446,16 +459,22 @@ func (s *NodeService) Delete(id int) error {
 	if err := db.Select("guid").Where("id = ?", id).First(&n).Error; err == nil {
 		guid = n.Guid
 	}
-	if err := db.Where("id = ?", id).Delete(model.Node{}).Error; err != nil {
-		return err
-	}
-	if err := db.Where("node_id = ?", id).Delete(&model.NodeClientTraffic{}).Error; err != nil {
-		return err
-	}
-	if guid != "" {
-		if err := db.Where("node_guid = ?", guid).Delete(&model.NodeClientIp{}).Error; err != nil {
+	// Delete the node row and its per-node child rows atomically. Remove the
+	// children (traffic baselines, IP attribution) before the parent node row so
+	// the ordering already matches a future ON DELETE constraint. Delete stays
+	// tolerant of a missing node row so it can still clean up orphaned baselines.
+	if err := db.Transaction(func(tx *gorm.DB) error {
+		if err := tx.Where("node_id = ?", id).Delete(&model.NodeClientTraffic{}).Error; err != nil {
 			return err
 		}
+		if guid != "" {
+			if err := tx.Where("node_guid = ?", guid).Delete(&model.NodeClientIp{}).Error; err != nil {
+				return err
+			}
+		}
+		return tx.Where("id = ?", id).Delete(&model.Node{}).Error
+	}); err != nil {
+		return err
 	}
 	if mgr := runtime.GetManager(); mgr != nil {
 		mgr.InvalidateNode(id)
diff --git a/internal/web/service/node_delete_orphan_test.go b/internal/web/service/node_delete_orphan_test.go
new file mode 100644
index 000000000..11c2775db
--- /dev/null
+++ b/internal/web/service/node_delete_orphan_test.go
@@ -0,0 +1,51 @@
+package service
+
+import (
+	"testing"
+
+	"github.com/mhsanaei/3x-ui/v3/internal/database/model"
+)
+
+// TestNodeDelete_BlocksWhenInboundsAttached guards DB-002: a node that still
+// owns inbounds must not be deletable (which would orphan those inbounds with a
+// dangling node_id), while a node with none deletes cleanly together with its
+// traffic baselines.
+func TestNodeDelete_BlocksWhenInboundsAttached(t *testing.T) {
+	db := initTrafficTestDB(t)
+	svc := &NodeService{}
+
+	node := &model.Node{Name: "n1"}
+	if err := db.Create(node).Error; err != nil {
+		t.Fatalf("create node: %v", err)
+	}
+	createNodeInbound(t, db, node.Id, "n1-in-443", 443)
+
+	// With an inbound attached, Delete must fail and leave node + inbound intact.
+	if err := svc.Delete(node.Id); err == nil {
+		t.Fatal("Delete should fail while an inbound is still attached")
+	}
+	var nodeCnt, ibCnt int64
+	db.Model(&model.Node{}).Where("id = ?", node.Id).Count(&nodeCnt)
+	db.Model(&model.Inbound{}).Where("node_id = ?", node.Id).Count(&ibCnt)
+	if nodeCnt != 1 || ibCnt != 1 {
+		t.Fatalf("after blocked delete: node=%d inbound=%d, want 1/1", nodeCnt, ibCnt)
+	}
+
+	// Detach the inbound and seed a traffic baseline; Delete now succeeds and
+	// cleans the baseline.
+	if err := db.Where("node_id = ?", node.Id).Delete(&model.Inbound{}).Error; err != nil {
+		t.Fatalf("detach inbound: %v", err)
+	}
+	if err := db.Create(&model.NodeClientTraffic{NodeId: node.Id, Email: "gone"}).Error; err != nil {
+		t.Fatalf("seed baseline: %v", err)
+	}
+	if err := svc.Delete(node.Id); err != nil {
+		t.Fatalf("Delete (no inbounds attached): %v", err)
+	}
+	var baseCnt int64
+	db.Model(&model.Node{}).Where("id = ?", node.Id).Count(&nodeCnt)
+	db.Model(&model.NodeClientTraffic{}).Where("node_id = ?", node.Id).Count(&baseCnt)
+	if nodeCnt != 0 || baseCnt != 0 {
+		t.Fatalf("after delete: node=%d baseline=%d, want 0/0", nodeCnt, baseCnt)
+	}
+}