Abstract: To study the influence of the coupling effect of chloride erosion and sand liquefaction on the seismic performance of bridge pile-pier,a seismic analysis model for the liquefaction site-pile-pier was built.The reliability of the modeling method was verified by comparing with shaking table test results.Taking a bridge pile-pier as the engineering background,four types of seismic analysis models were built:model for non-liquefied site and non-corroded pile-pier (Model 1),model for liquefied site and non-corroded pile-pier (Model 2),model for non-liquefied site and corroded pile-pier (Model 3),and model for liquefied site and corroded pile-pier (Model 4).Dynamic time history analysis for the models was conducted under 17 near-fault ground motions.The seismic response of the 4 models,such as the ultimate and residual drift ratios of the pier,the maximum curvature ductility factor and moment of the pile-pier,were compared with each other.The results show that both sand liquefaction and chloride erosion would increase the response of the pier obviously.The ultimate and residual drift ratios of the pier in Model 2 are 1.20 and 1.55 times of that in Model 1.And the ultimate and residual drift ratios of the pier in Model 3 are 1.27 and 1.23 times of that in Model 1.The sand liquefaction would increase the damage to the pile.The maximum curvature ductility factor of the pile in Model 2 is 1.23 times of that in Model 1,and the damage zone of the pile in Model 2 would be increased compared with that in Model 1.With the increase of the corrosion to the pier,the maximum curvature ductility factor of the pier would be increased,while it would be decreased in pile.Also,the maximum moment of the pile-pier would be decreased with the increase of the corrosion to the pier.The displacement and plastic damage of the pile-pier would further be increased under the coupling effect of chloride erosion and sand liquefaction.