The traditional linear elastic model cannot simulate the nonlinear seismic response analysis of RCC gravity dam in strong seismic regions．This paper analyzes? the seismic damage characteristics of Ludila RCC dam, when dam and foundation material nonlinearity? are considered at the same time. The main conclusions are as follows: When the foundation rock mass and the dam use the nonlinear materials, the foundation near dam toe is damaged, and with the continuous ground motion, the damage cracks extend gradually to the depth of the foundation. Thus, the stress redistribution of dam body and the stress concentration release at the juncture of dam foundation, which will not cause the earthquake damage at the dam foundation junction. Therefore the earthquake damage area and damage degree of the dam are reduced, which makes the dam more partial safety. The result will be more close to the actual, which has certain reference significance to the guiding project.