Aiming at the multi-aircraft flight simulation system poor expansibility in the past, developed the system based on the new distributed simulation technology framework, used the time synchronization and data filtering technology to improve the expansibility. It started with developing process of the multi-aircraft flight simulation system, introduced the high level architecture and the federation structure of the system in brief. It focused on the key technologies and their specific implementation methods to raise the multi-computer flight simulation system expansibility. The study can improve the complexity of the expansion of large scale simulation system for reference.