Differential planetary roller screw mechanism is a kind of mechanical transmission mechanism with high reduction ratio,which combines ring groove drive with thread meshing.In order to explore the dynamic characteristics of differential planetary roller screw,the structure and motion principle of a novel differential planetary roller screw were studied.The 3D model of the differential planetary roller screw mechanism was established,and the model was imported into the virtual prototype analysis software.The appropriate connection relationship was set up,and the kinematics and dynamics analysis of the 3D model was carried out.The results show that the motion in the virtual prototype is consistent with the motion analysis,which verifies the rationality of the motion analysis.When the load is applied to the nut,the ring groove design between the roller and the nut makes the contact force fluctuation more regular;with the load continues to increase,the contact force fluctuation between the screw and the roller,the nut and the roller also continues to increase,which aggravates the wear inside the mechanism and shortens the operating life of the mechanism.