Aiming at the trajectory planning problem of 6-DOF robots, the traditional B-spline trajectory planning method is used, and combine with the improved particle swarm optimization algorithm to improve the efficiency and stability of the manipulator under the premise of passing through the given path points. This method uses the improved particle swarm optimization (PSO) algorithm, optimizes the basic PSO algorithm, improves its shortcomings of easily falling into local optimum, and can quickly and accurately get the optimal solution. Through the simulation experiment, we can see that this method is feasible, and under the premise of satisfying the kinematic constraints, the running time is shorter and the fluency is better.