The compression of the Qinghai- Tibet Plateau andthe Sichuan Basin resulted in the formation of the Longmenshan fault zone and the uplift of its mountains. Based on the regional plate motion characteristics near the Longmenshan Mountain and the mechanical properties of deep rock mass, evolution process of regional tectonic system in the Longmenshan overa time span of 7.0 million years are simulated and reconstructed by FLAC3D. The results show that faults F1, F2 and F3 wereformed successively under the action of plate movement. The through faults have a strong controlling effect on the uplift of the surface for when they pass through the surface, Longmenshan and the western Sichuan plateau continue to uplift with an average uplift rate of about 1.38 mm/yr. However, while the West Sichuan depression to the east of the Longmenshan fault zone has only a small amount of uplift, the western Sichuan plateau was uplifted about 8996 m, resulting in a height difference of about 6000 m in this area. The simulated topographic characteristics are generallysimilar to the current topographic features. Based on the simulation results and the measured data, the evolutionary process map of the formation of the Longmenshan fault zone and its adjacent regional topography is drawn.Itshows that plate compression, fault plastic dislocation, surface erosion, sedimentation and other factors play an important role in the shaping process of topography and geomorphology.