A finite-time control scheme under input constraints is proposed for a class of nonlinear systems with high-order mismatched uncertainties,based on finite-time Lyapunov stability theory.First of all,a finite-time controller is designed by utilizing the technique of adding a power integrator.Then,when the output of the controller exceeds the bounded upper output,the Backstepping feedback idea is used to verify that the system is stable in finite time after the controller reaches saturation,thus to realize the segmentation of the input constrained problem.It is proved mathematically that with the proposed scheme,the closed loop system is stable in finite time,which ensures that the output of the controller designed with the proposed method is always within the given allowable saturation limit,and the controlled system is stabilized in finite time.Simulation results have proved the effectiveness of the proposed method.