An active disturbance rejection and sliding mode controller based on a reference model is studied. It comprises an active disturbance rejection controller and a global sliding mode controller. The active disturbance rejection controller with a tracking differentiator is designed according to the reference model, which regulates the reference model output to track the command input signals accurately. The global sliding mode controller regulates the controlled plant output of a servo system to track the reference model output in high precision. Experiments results of the opto-electronic platform servo system demonstrate that the new controller could compensate the parameters’ uncertainty and the nonlinear disturbance and increase the tracking precision of the servo system. The system is globally robust.