To address the displacement tracking problems of actuator saturation, state constraints, load disturbance and parameter uncertainties for continuous casting mold driven by servo motors, a Backstepping control strategy based on the extend state observer (ESO) and full states constraint is designed. Firstly, considering the problem of actuator input saturation, the mathematical model of the system is established. Secondly, a linear extended state observer (ESO) is employed for estimating the load disturbances and parameter uncertainties in real time, and the observer convergence of the observation error is analyzed. Thirdly, the problem of actuator saturation and tracking error states constraint is considered, and an auxiliary state variable is introduced to ensure the presetting range of the tracking error, and a Backstepping controller is designed. Finally, the closed-loop system stability is proved using the Lyapunov theorem, and simulations demonstrate the effectiveness of the proposed control method.