Abstract: This article is based on the monitoring data of Geheyan project to invert the elastic modulus of concrete dam by intelligent method.Firstly,the statistical model is established with stepwise regressions.The water pressure component of displacement is gained by the structural analysis by ANSYS under different elastic modulus and water level.The learning samples are constructed and trained in the networks.So,the average elastic modulus is gained.It is proved that the elastic modulus gained by this method is close to the real modulus and provides the reliable reference for evaluating the safe state of dam.?