In order to verify the feasibility of the certain type anti-riot grenade launcher, virtual prototype technology has been applied in automatic weapon research, and some numerical simulation analysis has been studied by using dynamic simulation software. The three-dimensional solid model was built by SolidWorks software according to ADAMS software’s modeling principle. The three-dimensional model was inputted in the environment of ADAMS after reasonable simplification, and the virtual prototype model was built by defining the kinematic joints, constraints, loads. Based on that, the automatic mechanism, firing mechanism and feeding mechanism were simulated. The results indicate that the model is reasonable and the base was established for further work.