Vortex induced vibration control for long span bridge is studied. A nonlinear, coupling and uncertain dynamic model of the long span bridge is considered. Because it is difficult to design the controller for the long span bridge vibration control system, the nonlinear and coupling uncertain control system is simplified, and a linear model is obtained. Then, based on sliding mode control approach, an optimal controller is designed for the long span bridge. Numerical simulations illustrate the effectiveness of the proposed controller.