Abstract: The problem of sliding mode control for time-delay systems with uncertain input is studied in the presence of unmeasurable states and the uncertainties of state parameters and control input matrix.In order to overcome the effects of uncertainties and time-delay on system stability,an integral switching function is chosen in the space of state estimation,and then a sliding mode controller based on state observer is proposed.The reachability of the designed switching surface is proved.A sufficient condition is derived based on Lyapunov theory to guarantee the asymptotical stability of the closed-loop system.A numerical simulation verifies the effectiveness of the proposed method.