Abstract: In this paper a remote 3D dynamic assembling/disassembling process simulation system for mechanical product maintenance is proposed. Detailed information models for the server and the client, continual control algorithm, synchronous control method, system architecture and protocols for collaborative assembling/disassembling processes are described. The system is developed mainly by means of Java, VRML and network database technologies. An application case is given, and the conclusion and future work are finally presented. The system can be used to improve the product after-sale service, for serving customers better.