In order to improve the maneuverability and safety of the air cushion vehicle (ACV), considering the internal uncertainties, external disturbances, chattering in sliding mode control, the second order nonsingular terminal sliding mode (SONTSM) controller with extended state observer (ESO) is designed to achieve the course control of ACV. The course controller includes two parts: second order nonsingular terminal sliding mode heading controller and extended state observer. The SONTSM controller is designed by combining the linear sliding surface with the nonsingular terminal manifold, which guarantees the tracking error asymptotically converges to zero in finite time and reduces the chattering in the sliding mode control. To reduce the chattering phenomena in the sliding control further, an ESO is introduced to estimate the nonlinear uncertainties and external disturbances of the ACV. Combining the ESO with the SONTSM controller, the new control law based SONTSM controller and ESO is designed. The stability of closed loop system is proved via Lyapunov analysis. Finally, a series of simulation experiments for a certain ACV are carried out under deferent wind disturbance conditions to evaluate the applicability robustness and superiority of the proposed approach.