Although located in the very low intensity area, the superstructure of Daxinglu Ramp Bridge sustained huge damage in Wenchuan earthquake. The longitudinal displacement of superstructure at the joint was about 400mm, which outdistanced the average displacement of all the other bridges in this area. In this paper, finite element model of the ramp bridge is made by general FEA software and the damage of the ramp bridge is analyzed by using nonlinear dynamic time history method. The results are obtained as follow: (1) the displacements restriction capacity of bearing system is reduced greatly by setting too many movable pot rubber bearings in the bridge. (2) The earthquake record near the bridge site is a typical long period ground motion. The extended natural period of the damaged bridge absorbed more but not less energy from the long period ground motion, which aggravated the damage.