A sliding mode control method based on nonlinear disturbance observer and nominal model is proposed to track the trajectory of manipulator with uncertain interference. A dynamic model of the manipulator is established, a sliding mode control law is designed, and the stability of the system is verified by the Lyapunov stability theory. A nonlinear disturbance observer is introduced to improve the performance of the control system. The results show that the control method reduces the unmodelled dynamic errors and the influence of uncertain external interference. Furthermore, simulation results based on Matlab prove that compared with the traditional PD position control method, proposed method has higher accuracy and better robustness.