Firstly,comparative study for the spiral bevel gear dynamic character is carried out by taking pressure angle,blade tip radius and ratio of gear tooth thickness these parameters into consideration and based on the modeling of mult-body and mult-DOF dynamics equation and theory of mixed elastohydrodynamic lubrication（EHL）time-vary friction.Considering the influence of non-linear parameters,such as time-vary friction force,dynamic mesh force and transmission error and backlash,at the same time take into account in practical application,the gear meshing in a mixed elastohydrodynamic lubrication（EHL）consisted of asperity contact and full film lubrication.The dynamic response of system is solved,the result shows that it has better performance of dynamic response and dynamic transmission error after the optimization of design parameters.Last,through the bench test,the accuracy of the research result is verified.