diff --git a/czsc/features/__init__.py b/czsc/features/__init__.py
index f182d0dbd..08bc3518e 100644
--- a/czsc/features/__init__.py
+++ b/czsc/features/__init__.py
@@ -4,6 +4,8 @@
 email: zeng_bin8888@163.com
 create_dt: 2024/02/14 17:48
 describe: 时序特征因子库
+
+因子函数编写规范：https://s0cqcxuy3p.feishu.cn/wiki/A9yawT6o1il9SrkUoBNchtXjnBK
 """
 
 from .ret import (
@@ -15,4 +17,11 @@
     RET006,
     RET007,
     RET008,
+)
+
+from .vpf import (
+    VPF001,
+    VPF002,
+    VPF003,
+    VPF004,
 )
\ No newline at end of file