For the network testing needs of the TDMA MANET terminal, this paper proposed a method of simulation. By transplanting the terminal software and constructing the network simulation environment with centralized slot scheduling, we can test the large scale network base on it, maintaining the whole network function of the terminal. This paper designed and implemented the simulation system. Compared to physical or semi-physical test, the system has advantages of effectiveness and low cost. Already using in projects, the system works well in the network function and performance verification of TDMA MANET terminals.