diff --git a/library/think/model/relation/BelongsToMany.php b/library/think/model/relation/BelongsToMany.php
index cd334892..026334ed 100644
--- a/library/think/model/relation/BelongsToMany.php
+++ b/library/think/model/relation/BelongsToMany.php
@@ -374,13 +374,13 @@ class BelongsToMany extends Relation
     protected function belongsToManyQuery($foreignKey, $localKey, $condition = [])
     {
         // 关联查询封装
-        $tableName  = $this->query->getTable();
-        $relationFk = $this->query->getPk();
-        $table      = $this->pivot->getTable();
-        $query      = $this->query->field($tableName . '.*')
+        $tableName = $this->query->getTable();
+        $table     = $this->pivot->getTable();
+        $query     = $this->query->field($tableName . '.*')
             ->field(true, false, $table, 'pivot', 'pivot__');
 
         if (empty($this->baseQuery)) {
+            $relationFk = $this->query->getPk();
             $query->join($table . ' pivot', 'pivot.' . $foreignKey . '=' . $tableName . '.' . $relationFk)
                 ->where($condition);
         }