Ball and plate system is a high order nonlinear system with the character of open loop instability. Based on the Lyapunov stability theory and dual closed-loop control strategy, a sliding mode variable structure position controller is designed, and the particle swarm optimization algorithm is used to optimize the sliding mode parameters with the aim of improving the control precision and reducing the sliding mode chattering elimination. Simulation results show that the sliding mode variable structure control algorithm has better tracking and robust performance compared with traditional dual closed-loop PID control.