Abstract: Jinsha Jiang Bridge is located in the deep gorge of the Jinsha River Tiger Leaping Gorge town, a high seismic intensity area. The rock slope at left of the bridge and on the side of Shangri-La City is affected by terrain steep unloading fractures. It is importance to study the slope rock stability in loads of engineering. According to the engineering geological conditions and the characteristics of joints, Barton model and shear stress test, strength parameters of rock mass structure surface are discussed. Then, the failure trend in gravity and engineering are analyzed by bottom friction test. In order to evaluate the damage trends of the rock mass under the different loading conditions such gravity, bridge loading and seismic load, a calculation model based on the geological model and slope stability is simulated and analyzed using Discrete Element Method(DEM).The numerical analysis results indicate the effect of degradation of discontinuities on the slope stability. The results have shown that the destruction of rock mass under the gravity and bridge foundation is mainly concentrated within 30m depth of the slope. The slope under loading may cause loosening strength along joint planes. But under earthquake and bridge loads, bridge foundation should be strengthened.