The factors are given, which effect the performance for sliding mode variable structure control. A new design
method for a class of nonlinear system with uncertainties is presented by using the gain-scheduling variable structure controllers. In order to improve the control performance, restrain the chattering of the controller and decrease the cost of control power, the parameters of the sliding mode, the layer and the control gain are scheduled by the switch function. The simulation results show the effectiveness of the proposed approach.