This paper aims to prove the effectiveness of MR damper as a smart control device when controlling the earthquake invoked transverse vibration of a two-span simple bridge. Applying a 40% of Kobe earthquake and a 120% of El-centro on a target structure, experiments were performed under two conditions: passive on (current on) and Lyapunov control algorithm embedded. MR damper's control performance was analyzed and contrasted under each different condition. It was concluded that MR damper was effective in controlling the vibration of the bridge.