Robot trajectory planning is the core to achieve high - speed and high - precision running. Reasonable robot trajectory planning not only needs to meet the requirements of the kinematics, but also needs to meet the requirements of the dynamics. Under the same conditions of drive motor, increasing the speed and load of robot is the difficulty of robot trajectory planning. The robot will be analyzed in depth by advanced python software in this paper. In the joint space, the trajectory by polynomial of degree five is fitted. And dynamic models are added to the trajectory planning. The fitting curves show that the displacement, velocity, acceleration and jerk are continuous and derivable in the joint space and work space. In each time period of peak torque, peak power tends to the same value. The speed and the life of the moving parts are improved effectively.