Abstract: A method for optimizing the compaction quality control index of dams is proposed. Using the collected dry density of field soil samples, the statistics (mean, standard deviation and correlation distance) are determined. According to the correlation between the deformation parameters and the dry density of soils, the random fields of material parameters are established, and the random finite element analysis is carried out to predict the structural responses and safety of dams. Based on the quadratic polynomial, the response surface equation for the statistics of dry density of soils and dam response is established, and the exceeding probability expression is derived. In order to improve the dam safety, the statistics of dry density of soils are further optimized, which provides guidance for the adjustment of construction parameters. Through a practical project, the influence laws of material uncertainty are studied at different filling stages. The uncertain deformation response analysis tends to be stable. The statistics of core wall materials have a great effect on the maximum settlement and deformation gradient. By adjusting the exceeding probability, the statistics of dry density of soils in each partition can be obtained, so as to guide the dam construction and improve the control level of dam deformation as well as the safety evaluation accuracy.