In order to load Java class file during the Java application runtime and without affecting the normal operation of other functional modules, the realization of Java dynamic class loading method is given based on the java virtual machine (JVM) mechanism. Java Class Loader architecture, theory of dynamic class loading mechanism, the implementation process are analyzed, and which are applied to the file release module of web site management platform system. The file release module is designed to make static web pages and website management system linked. Through the custom loader to loading encryption of Java class files. In a hot swap way to implement the deployment of secondary website, enhance the site management platform's flexibility and expansibility.