diff --git a/site/src/site/sphinx/en/redefine.md b/site/src/site/sphinx/en/redefine.md
new file mode 100644
index 000000000..4ce2af248
--- /dev/null
+++ b/site/src/site/sphinx/en/redefine.md
@@ -0,0 +1,26 @@
+redefine
+========
+
+Load the external `*.class` files and *re-define* the JVM-loaded classes.
+
+Reference: [Instrumentation#redefineClasses](https://docs.oracle.com/javase/8/docs/api/java/lang/instrument/Instrumentation.html#redefineClasses-java.lang.instrument.ClassDefinition...-)
+
+F.Y.I
+
+1. Re-defined classes cannot be restores any more;
+2. Re-definition can fail (like adding a new field); for more information, please refer to JDK documentation
+
+### Options
+
+|Name|Specification|
+|---:|:---|
+|[c:]|hashcode of the class loader|
+|[p:]|absolute path of the external `*.class` (multiple paths supported)|
+
+
+### Usage
+
+```
+   redefine -p /tmp/Test.class
+   redefine -c 327a647b -p /tmp/Test.class /tmp/Test\$Inner.class
+```