The virtual prototype model of certain grenade launcher system is established by taking using of software Solidworks and ADAMS. Control method of continuous firing is put forward according to the weapon automatic action, and the model is confirmed. The results indicate that simulation is consistent with the experiment data. Then, the feeding system, bolt head and the impact force between bolt head and barrel extension are simulated. The parameters that couldn’t be get from experiments are obtained. Analyzing results indicate that analyzing dynamic characteristics of the grenade launcher system by virtual prototype model is feasible.