In order to improve the gradual deterioration of the dynamic performance of the spatial parallel mechanism caused by the lubrication clearance effect, a dynamic optimization method of the spatial parallel mechanism considering the lubrication clearance effect was proposed by taking the 3-R[TXX-]RPaR redundant parallel mechanism as the research object. Firstly, the kinematic model of the lubrication clearance of the revolute pair and the oil film bearing capacity model were established. The transition force model of the contact state was derived, and the dynamic model of the 3-R[TXX-]RPaR redundant parallel mechanism considering the lubrication clearance of the revolute pair was established. Then, the objective function was set up to optimize the dynamic response error of the end-effector and the constraint reaction force at the clearance joint. By optimizing the quality of the end-effector and the moment of inertia, the degradation effect caused by the clearance of the kinematic pair was alleviated, and the dynamic optimization model of the 3-R[TXX-]RPaR redundant parallel mechanism considering the lubrication clearance effect was established. Finally, the effectiveness of the established dynamic model was experimentally verified, the influence of the two objective functions on the optimization effect was compared and analyzed to select the best optimization method, and the dynamic characteristics of the spatial parallel mechanism considering the lubrication clearance effect before and after optimization were analyzed. The results showed that the optimization reduced the peak value of the constraint reaction force at the lubrication clearance revolute joint by 16.16%. The research result can provide theoretical support for improving the dynamic performance of spatial parallel mechanism by improving the clearance effect.