A sliding mode variable structure control method based on the Lyapunov equation is proposed for the non-matching uncertainty in the dynamic model of hypersonic vehicles.A tracking-oriented control system model with non-matching disturbances is established to estimate non-matching disturbances by introducing a nonlinear perturbation observer.A new sliding-mode surface consisting of the perturbation estimates of the velocity subsystem and the altitude subsystem is proposed,and a sliding-mode controller is derived for the non-matching disturbances.The stability of the system is proved based on the stability criterion starting from the Lyapunov equation,from which the relationship between the tracking error accuracy of the two subsystems and the estimation error of the unmatched disturbance is obtained.The simulation results show the correctness of the method.