diff --git a/README.md b/README.md
index ff6083fa31b0efdb66e205da5ea267d91b76d827..1cbfee4721e69be1ef54041dc96db34314f95405 100644
--- a/README.md
+++ b/README.md
@@ -90,6 +90,7 @@ Json.fromJson[Person](json)
 
 - 说明
   - 支持普通类和样例类。
+  - 仅支持对主构造函数使用。   
   - 如果该类没有伴生对象，将生成一个伴生对象来存储`builder`方法和类。
 
 - 示例
diff --git a/README_EN.md b/README_EN.md
index 7e983e0cbaaea642de4b52335ae3e8c6972d6d9c..26bcdb4bf7021e728d57014b474f0f9a8452f375 100644
--- a/README_EN.md
+++ b/README_EN.md
@@ -92,6 +92,7 @@ The `@builder` used to generate builder pattern for Scala classes.
 
 - Note
   - Support `case class` / `class`.
+  - Only support for **primary constructor**.  
   - If there is no companion object, one will be generated to store the `builder` class and method.
 
 - Example