A dynamic terminal sliding mode control method based on disturbance observer is presented to solve the problem of speed and position error jump when a mobile robot is subject to external irregular disturbance. Based on the kinematics model, a virtual controller is designed using Lyapunov method, and a non-singular dynamic terminal sliding mode track tracking controller is further designed. To reduce the influence of external disturbance on the system, a nonlinear disturbance observer is designed to compensate the disturbance of the controller. Finally, the method proposed in this paper is compared with the adaptive sliding mode control method by simulation. The results show that the line speed and angular speed of the adaptive sliding mode control method change by 1.4 m/s and 1.24 rad/s respectively when the 15s disturbance changes step by step. The speed jump amplitude of the method presented in this paper is less than 1/10 of that of the adaptive sliding mode control method. The simulation results show that the proposed method can effectively suppress the influence of disturbance on the system and reduce the jump amplitude of the speed and posture errors of the mobile robot.