diff --git a/modules/EcommerceFinance/Services/UpstreamSchemaCatalogSynchronizer.php b/modules/EcommerceFinance/Services/UpstreamSchemaCatalogSynchronizer.php
index 6befd077..a70f0a05 100644
--- a/modules/EcommerceFinance/Services/UpstreamSchemaCatalogSynchronizer.php
+++ b/modules/EcommerceFinance/Services/UpstreamSchemaCatalogSynchronizer.php
@@ -53,10 +53,7 @@ class UpstreamSchemaCatalogSynchronizer
         }
 
         $now = now();
-        $normalized = array_map(
-            fn (array $row): array => $this->normalize($definition['key'], $row, $now),
-            $rows
-        );
+        $normalized = $this->normalizeAndDeduplicate($definition['key'], $rows, $now);
         $objectCount = collect($normalized)
             ->map(fn (array $row): string => $row['schema_name'] . '.' . $row['object_name'])
             ->unique()
@@ -116,6 +113,30 @@ class UpstreamSchemaCatalogSynchronizer
         ];
     }
 
+    /**
+     * 部分旧 SQL Server 库的 INFORMATION_SCHEMA 会返回重复字段。
+     * 共享库的目录键不允许重复，因此写入前按数据库常见的不区分大小写规则去重，
+     * 避免少量脏元数据让整个来源的目录同步回滚。
+     */
+    private function normalizeAndDeduplicate(string $source, array $rows, $now): array
+    {
+        $unique = [];
+
+        foreach ($rows as $row) {
+            $normalized = $this->normalize($source, $row, $now);
+            $identity = implode("\0", [
+                mb_strtolower($normalized['source_key'], 'UTF-8'),
+                mb_strtolower($normalized['schema_name'], 'UTF-8'),
+                mb_strtolower($normalized['object_name'], 'UTF-8'),
+                mb_strtolower($normalized['column_name'], 'UTF-8'),
+            ]);
+
+            $unique[$identity] ??= $normalized;
+        }
+
+        return array_values($unique);
+    }
+
     private function nullableInteger(mixed $value): ?int
     {
         return $value === null || $value === '' ? null : (int) $value;
diff --git a/tests/Unit/EcommerceFinance/UpstreamSchemaCatalogSynchronizerTest.php b/tests/Unit/EcommerceFinance/UpstreamSchemaCatalogSynchronizerTest.php
index 7fa5e1bf..e9b98d62 100644
--- a/tests/Unit/EcommerceFinance/UpstreamSchemaCatalogSynchronizerTest.php
+++ b/tests/Unit/EcommerceFinance/UpstreamSchemaCatalogSynchronizerTest.php
@@ -101,6 +101,51 @@ class UpstreamSchemaCatalogSynchronizerTest extends TestCase
         }
     }
 
+    public function test_duplicate_metadata_rows_do_not_abort_catalog_sync(): void
+    {
+        $duplicate = [
+            'schema_name' => 'dbo',
+            'object_name' => 'tuihuo',
+            'object_type' => 'table',
+            'column_name' => '发货量',
+            'ordinal_position' => 3,
+            'data_type' => 'decimal',
+            'max_length' => null,
+            'numeric_precision' => 18,
+            'numeric_scale' => 2,
+            'is_nullable' => 'YES',
+        ];
+        $query = Mockery::mock(UpstreamReadOnlyQuery::class);
+        $query->shouldReceive('select')->once()->andReturn([
+            $duplicate,
+            $duplicate,
+            [
+                ...$duplicate,
+                'column_name' => '序号',
+                'ordinal_position' => 1,
+                'data_type' => 'int',
+                'numeric_precision' => 10,
+                'numeric_scale' => 0,
+            ],
+        ]);
+        $factory = Mockery::mock(UpstreamReadOnlyQueryFactory::class);
+        $factory->shouldReceive('forSource')->once()->with('catalog_test')->andReturn($query);
+
+        $result = (new UpstreamSchemaCatalogSynchronizer(
+            app(UpstreamSourceRegistry::class),
+            $factory
+        ))->sync('catalog_test');
+
+        $this->assertSame(1, $result['objects']);
+        $this->assertSame(2, $result['columns']);
+        $this->assertSame(1, DB::table('upstream_schema_columns')
+            ->where('source_key', 'catalog_test')
+            ->where('schema_name', 'dbo')
+            ->where('object_name', 'tuihuo')
+            ->where('column_name', '发货量')
+            ->count());
+    }
+
     private function existingRow(): array
     {
         return [