Abstract: Detailed investigation was carried out on the failure mode of retaining structures caused by the Wenchuan earthquake along highways and railways summing up to 3 000 km in length in Sichuan. From the investigation results,two key technical problems,performance-based design method of retaining structures and the action point of seismic earth pressure,were discussed. It is believed that earthquake-resistant design of retaining structures should consider the requirement of the displacement of retaining walls on three seismic design levels. Performances of retaining structures associated with the three seismic levels may be defined as follows:the performance requirement for the three seismic design levels is that the displacement index is less than 1.0% for a small earthquake level,below 3.5% for a moderate earthquake level and less than 6.0% for a large earthquake level. The research shows that the action point of resultant seismic earth pressure is at the location of 0.45 to 0.63 times wall height above the foot of retaining walls,and the location of the action point is impacted by the wall height and backfill properties.