diff --git a/catalog/common/models.py b/catalog/common/models.py
index acb804b0..16978c12 100644
--- a/catalog/common/models.py
+++ b/catalog/common/models.py
@@ -80,6 +80,18 @@ class IdType(models.TextChoices):
     ApplePodcast = "apple_podcast", _("苹果播客")
 
 
+IdealIdTypes = [
+    IdType.ISBN,
+    IdType.CUBN,
+    IdType.ASIN,
+    IdType.GTIN,
+    IdType.ISRC,
+    IdType.MusicBrainz,
+    IdType.RSS,
+    IdType.IMDB,
+]
+
+
 class ItemType(models.TextChoices):
     Book = "book", _("书")
     TV = "tv", _("剧集")
@@ -269,17 +281,7 @@ class Item(SoftDeleteMixin, PolymorphicModel):
     @classmethod
     def get_best_lookup_id(cls, lookup_ids):
         """get best available lookup id, ideally commonly used"""
-        best_id_types = [
-            IdType.ISBN,
-            IdType.CUBN,
-            IdType.ASIN,
-            IdType.GTIN,
-            IdType.ISRC,
-            IdType.MusicBrainz,
-            IdType.RSS,
-            IdType.IMDB,
-        ]
-        for t in best_id_types:
+        for t in IdealIdTypes:
             if lookup_ids.get(t):
                 return t, lookup_ids[t]
         return list(lookup_ids.items())[0]
diff --git a/catalog/forms.py b/catalog/forms.py
index f29ec21b..941a9984 100644
--- a/catalog/forms.py
+++ b/catalog/forms.py
@@ -27,7 +27,7 @@ def _EditForm(item_model: Item):
             label=_("主要标识类型"),
         )
         primary_lookup_id_value = forms.CharField(
-            required=False, label=_("主要标识数据通常由系统自动检测，请勿随意更改，不确定留空即可")
+            required=False, label=_("主要标识数据通常由系统自动检测，请勿随意更改现有值，新增条目不确定留空即可")
         )
 
         class Meta:
diff --git a/catalog/views.py b/catalog/views.py
index 6d8ce067..c52cf8f1 100644
--- a/catalog/views.py
+++ b/catalog/views.py
@@ -8,7 +8,7 @@ from django.core.exceptions import BadRequest, PermissionDenied, ObjectDoesNotEx
 from django.db.models import Count
 from django.utils import timezone
 from django.core.paginator import Paginator
-from catalog.common.models import ExternalResource
+from catalog.common.models import ExternalResource, IdealIdTypes
 from .models import *
 from django.views.decorators.clickjacking import xframe_options_exempt
 from journal.models import Mark, ShelfMember, Review, query_item_category
@@ -159,7 +159,11 @@ def edit(request, item_path, item_uuid):
         item = get_object_or_404(Item, uid=get_uuid_or_404(item_uuid))
         form_cls = CatalogForms[item.__class__.__name__]
         form = form_cls(instance=item)
-        if item.external_resources.all().count() > 0:
+        if (
+            item.external_resources.all().count() > 0
+            and item.primary_lookup_id_value
+            and item.primary_lookup_id_type in IdealIdTypes
+        ):
             form.fields["primary_lookup_id_type"].disabled = True
             form.fields["primary_lookup_id_value"].disabled = True
         return render(request, "catalog_edit.html", {"form": form, "item": item})
@@ -167,7 +171,11 @@ def edit(request, item_path, item_uuid):
         item = get_object_or_404(Item, uid=get_uuid_or_404(item_uuid))
         form_cls = CatalogForms[item.__class__.__name__]
         form = form_cls(request.POST, request.FILES, instance=item)
-        if item.external_resources.all().count() > 0:
+        if (
+            item.external_resources.all().count() > 0
+            and item.primary_lookup_id_value
+            and item.primary_lookup_id_type in IdealIdTypes
+        ):
             form.fields["primary_lookup_id_type"].disabled = True
             form.fields["primary_lookup_id_value"].disabled = True
         if form.is_valid():