In the process of realization Internet-based visualization system of the protein molecules, system needs to allow users to use the system to observe the molecular structure of the local computer, that is, customers can generate the three-dimensional graphics from PDB file on the client computer. This requires Applet access to local file, related to the Applet security restrictions question. In this paper include two realization methods: 1.Use such as signature tools, key management tools and Policy Editor tools provided by the JDK to digital signature and authentication for Java Applet, breakthrough certain security restrictions in the browser. 2. Through the use of Servlet agent implement indirect access data methods, breakthrough the traditional Java Virtual Machine sandbox model restriction of Applet ability. The two ways can break through the Applet's security restrictions, but each has its own strengths.