In order to realize long-distance distributed interactive operation of virtual instrument in GL Studio, the key technology of this virtual training system is researched. The running environment and operation flow of virtual training system are analyzed, and the system overall design framework is given. Then, network communication based on hybrid protocol is designed to ensure data transfer fast and reliably. Multi-thread technology is used to improve the system response speed. Semaphore is adopted to synchronize threads, and the waste of external control time and resource is avoided. Finally, the key steps of multi-threaded and network communication in GL Studio are given. The research results provide referenced technical foundation for virtual training system which is concerting from single machine model to distributed collaborative training model, and has a certain industrial applications.