Abstract: In order to grasp the influence of wear clearance of spherical pair on dynamic response characteristics of spatial parallel mechanism， a dynamic modeling and response analysis method for spatial parallel mechanism considering the wear of spherical joints is proposed. The 3SPS-S spatial parallel mechanism is taken as the research object. The wear model of the spherical joint clearance is established based on the Archard wear model， the worn ball head and ball socket are obtained by calculating the wear depth and surface geometric reconstruction， and the dynamic model of the parallel mechanism considering spherical joint wear is es tablished. The numerical results are obtained by solving the above dynamic model. The change of dynamic response of mechanism before and after wear is compared and analyzed， and the influence of initial clearance value and load on dynamic response of mecha nism after wear is obtained. The results show that the worn irregular clearance has adverse effects on the dynamic characteristics of the parallel mechanism， and the increase of clearance value and the introduction of load can reduce the stability of the parallel mech anism.