In order to prolong the service life of the swing check valve and reduce the energy loss,by establishing the valve flap motion model,combined with the structural dynamics model,using the analysis module of Fluent and ANSYS/LS-DYNA finite element software,the valve flap movement and impact collision during the valve closing process were simulated and analyzed. Through analysis,it was shown that the fluid backflow has a hysteresis,the movement speed of the valve flap shows a parabolic rise,and the dynamic torque presents a process of slowly decreasing to suddenly increasing in the reverse direction when the valve is closing. Vortex phenomenon obvious occurs at the bottom of the valve flap,and there is a time difference in the change of fluid flow direction on the center line of the flow channel; In the process of collision and rebound,the peak stress appeared at the rounded corners of the back of the flap and the rocker rib,and the valve flap swings slightly and collides with the valve seat many times in a short time. The study results provided a reference for the design and optimization of the structural parameters of the valve.