Whether the bridge pile structures adjacent to the slopes can support the threats of the landslides im? pact determines that the bridge can provide safe service. Therefore，the research on the slope instability mechanism and the law of sliding mass impact on bridge pile structure under earthquake and rainfall is an urgent need for bridge engineering design and construction. Based on the advantages of Smoothed Particle Hydrodynamics method，such as tracking the time change of particle characteristics and simulating large deformation，a parallelized Smoothed Particle Hydrodynamics algorithm was proposed to simulate the process of earthquake-induced landslides impact on bridge pile structure. The effects of seismic acceleration amplitude，frequency spectrum，duration on analyzing law of impact by rainfall-induced landslide and earthquake-induced landslide on bridge pile structure were analyzed， and the effect of different number of threads on the efficiency of parallel computing were studied. The results showed that the increase of seismic acceleration amplitude can accelerate the soil sliding impact on bridge pile structure and increase the impact volume. There was a seismic acceleration critical value for the increase of soil sliding impact vol? ume. If it was greater than the critical value，the increase of soil sliding volume was larger. In a certain frequency range，the sliding velocity and impact volume of soil increased with the increase of the peak frequency of seismic re? sponse spectrum，and the impact of sliding soil on bridge pile structure was accelerated. With the increasing propor? tion of the earthquake duration，the displacement of the middle and rear edge of the slope increased obviously，and the impact volume of the sliding soil on the bridge pile structure also increased. The optimization algorithm can make full use of threads and greatly improve the computing efficiency.