Abstract: Soon after Wenchuan earthquake, the water levels of shallow uplift pressure and deep drainage observation holes at rear curtain of dam foundation declined, and dam foundation leakage increased significantly, which indicated that, because of earthquake, the micro-cracks in dam foundation rock and the curtain opened wider and permeability was enhanced. At the dam foundation part once acrylamide grouted, the water level stayed higher and recovery process was shorter, which showed that acrylamide grouting was of good seepage-prevention and anti- seismic effect. Wenchuan earthquake did not cause damage to dam stability, foundation rock mass or the curtain. About 9 months after the earthquake, anti-seepage performance of dam foundation recovered.