With the gearbox of a large-scale wind turbine as a study object, the virtual prototype model of gearbox is created based on UG and ADAMS softwares according to its design parameters such as structure and size. By rigid and flexible dynamics analysis for gearbox, the angular velocity and acceleration curves of the in-out shaft are obtained. Gear meshing forces and flexible body stress cloud using ADAMS are also obtained. It is verified that these results are coincided with the theoretical value through analysis and the simulation results of ADAMS are valid. The simulation results show that the design level of wind turbine gearboxes can be improved using the virtual prototype technology and lay a good foundation for further optimal design.