For multiple work sections and complicated work conditions, Inertia Release Mechanism contains complicated contact surfaces of parts, it is hard to design and analyze with traditional methods. In this paper, the detailed structure model of Inertia Release Mechanism was designed with UG, and its virtual prototype model was established with LMS Virtual. Lab Motion. Based on the model, system kinematics and dynamics were simulated and analyzed. The simulation results revealed that with virtual prototype technology, the design level and efficiency of Inertia Release Mechanism can be enhanced. The model can also be used for structure optimum design.