The rolling stone disaster will directly affect the use of the bridge structure in the mountainous area, and even lead to the deviation of the bridge pier, the falling beam and even the collapse of the entire bridge. In order to simulate the dynamic process of rock-rock impact piers more realistically, this paper combines engineering examples to establish a finite element model, and introduces the theory of collision dynamics analysis and the principle of numerical analysis. The LS-DYNA is used to analyze the structural dynamic response of different rolling stone quality and different rolling stone speeds. The research shows that the greater the mass of the rolling stone and the higher the speed, the more significant the impact on the pier damage.