Abstract: This paper addresses the high-order sliding mode control problem of nonlinear affine systems. By proper input and nonlinear state transformations, the system is first decomposed into two low dimensional subsystems: the linear subsystem involves the switching functions and related derivatives, and the nonlinear subsystem describes the sliding mode motion. A high-order sliding mode control law is then developed to achieve high-order sliding mode motion with prescribed dynamics. Finally, numerical simulations are performed for the posture model of a two-wheel driven nonholonomic mobile robot, and the results show that the proposed approach has considerable potentialities to lessen the chattering of sliding mode control systems.