The effect of solidliquid coupling has great influence on the kinematics and dynamics of the piston pump. The rigidflexible coupling model of the piston pump was established by using finite element analysis software. And the virtual prototype model of the solidliquid coupling was established based on this. The influence of the swash plate angle and the shaft velocity on the kinematics and dynamics characteristics of the piston pump was researched, as well as the change rules of the hydraulic pressure in the piston. The results show that the flow and pressure fluctuation amplitude of the pump are increased with the increase of swash plate angle; the acceleration of the piston is proportion to the square of the shaft velocity, meanwhile the hydraulic impact force of the pump is increased rapidly. The results provide a reference for the further analysis of the performance of the piston pump.