Abstract: As the last process of precision machining of complex curved blades, the processing quality of abrasive belt grinding directly affects the service performance and life of the blades. The traditional six-degree-of-freedom robot with multi-joint tandem connection has obvious weak rigidity, and its deformation resistance is not good when clamping large blades at the end. For this reason, a 4+2 degree of freedom blade grinding robot system is designed and developed. Research of complex surface blade grinding trajectory planning method is carried out with the self-developed grinding robot system. First of all, the kinematics model of the robot is established based on the D-H method. The forward and inverse solutions of robot kinematics are given. A trajectory planning method is proposed that comprehensively considers the interference between polishing tools and workpiece curvature, the influence of tool path spacing and trajectory point density on residual height. A collaborative motion model of two units is established to ensure the machining implementation of the blades. Finally, the correctness of the obtained grinding trajectory is verified through numerical control program simulation of the blade polishing trajectory.