diff --git a/alembic/versions/052_generation_task_bgm_config.py b/alembic/versions/052_generation_task_bgm_config.py
new file mode 100755
index 000000000..27bc4476e
--- /dev/null
+++ b/alembic/versions/052_generation_task_bgm_config.py
@@ -0,0 +1,64 @@
+"""#642 - 生成任务新增 bgm_config 字段
+
+Revision ID: 052_generation_task_bgm_config
+Revises: 051_generation_task_resolution
+Create Date: 2026-07-25
+
+Changes:
+1. generation_tasks 表新增 bgm_config 字段（JSON类型），存储用户自定义BGM配置
+2. 为空时使用默认空字典
+
+背景：
+#642 一键生成支持自定义BGM 功能在 SQLAlchemy 模型中加了 bgm_config 字段，
+但遗漏了 alembic migration，导致 staging 环境数据库没有该列，
+创建生成任务时直接 500。
+"""
+
+import sqlalchemy as sa
+
+from alembic import context, op
+
+revision = "052_generation_task_bgm_config"
+down_revision = "051_generation_task_resolution"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    conn = op.get_bind()
+    if context.get_context().dialect.name == "postgresql":
+        # 检查列是否已存在（幂等）
+        result = conn.execute(
+            sa.text(
+                "SELECT column_name FROM information_schema.columns "
+                "WHERE table_name = 'generation_tasks' AND column_name = 'bgm_config'"
+            )
+        )
+        if result.scalar() is not None:
+            return
+
+    op.add_column(
+        "generation_tasks",
+        sa.Column(
+            "bgm_config",
+            sa.JSON,
+            nullable=False,
+            server_default=sa.text("'{}'::json"),
+        ),
+    )
+
+
+def downgrade() -> None:
+    conn = op.get_bind()
+    if context.get_context().dialect.name == "postgresql":
+        # 检查列是否存在（幂等）
+        result = conn.execute(
+            sa.text(
+                "SELECT column_name FROM information_schema.columns "
+                "WHERE table_name = 'generation_tasks' AND column_name = 'bgm_config'"
+            )
+        )
+        if result.scalar() is None:
+            return
+
+    op.drop_column("generation_tasks", "bgm_config")