To study the anti-seismic performance of Lock-up device, the two computational models which are respectively uninstalled Lock-up device and installed Lock-up device on the arch bridge are established. Nonlinear time-history analyses are carried out by the Midas/Civil software in this paper. The interaction between pile and soil is considered in the analyses. The results show that the maximum shear forces of the tops and the maximum bending moments of the bottoms of all piers are quite uniform after the LUD are installed and that the displacements of the top of the fixed pier has been decreased.