Landing buffer is one of key parts to realize a soft landing on planet. Its cushioning performance is directly related to the success or failure of the soft landing on the planet surface. According to the given model of the mars lander, a reasonable simplified model of the lander is established in a three dimensional modeling software. In order to improve the analyzing accuracy of of the impact response in this landing process, the buffer performance of the lander is analyzed by the method of transient dynamics using a finite element software Patran/Dytran (MSC company). The simulation results are in agreement with the experimental data. Therefore, it is feasible to use the truss type mars lander. The simulation results and experimental data also provide references for future Mars exploration.