Abstract: The performance evaluation on a LEO/MEO satellite network is carried out by model-based analysis and software simulation, respectively. Firstly, the GSPN model of a double-layered satellite network is constructed and simplified, and then used to evaluate the network performance with SPNP4.0 software package. Then, the effectiveness of the results obtained by model-based analysis is verified in comparison with those by network simulation using OPNET, and some results are derived that the performance of double-layered constellation is better than that of single-layered one because processing and waiting delay become the main delay under high traffic condition.