The continuous development of industry has higher and higher load requirements for the robot arm, and the increase of load will affect the accuracy of the end of the robot arm. In this paper, the forward and inverse kinematics of a sevenaxis serial manipulator are analyzed by M-DH method and Jacobi iteration method. The trajectory planning of joint space is carried out by cubic function interpolation method. A dynamic model of the manipulator is established based on Lagrange equation, and the effectiveness of the model is verified by numerical methods. Finally, based on the positioning control, the relationship between the convergence rate of the end position error, the load quality and the control parameters is studied.