The virtual prototype model of tuned mechanism was built,and mistuned simulation of fraction was carried out.On the base of multibody system dynamics principle and method,double trail mechanism model of virtual prototype was established on software platform of PRO/E and ADAMS.The mechanism was simulated in kinetics to obtain its dynamic parameters,and the kinetic and dynamic response parameters were analyzed in case of mistuned fractional forces.The results show that the present method has a higher precious and lower cost,and the model built by this method can be easily to realize the dynamic simulation to obtain dynamics parameters,which provides a new analyzing approach on mechanism design. 