Based on the seepage monitoring data of Donggu earth-rock dam , this paper analyzed qualitatively the variation of the piezometric tube water level,potential and leak. The regression model of the piezometric tube water level is established and the influence factors of the piezometric tube water level is quatitatively analyzed. The results showed that the regression fitting effect is well,the saturation line of the dam tends to increase, the seepage flow tends to decrease, the overall permeability of the dam reduced and the dam seepage is normal. The analysis conclusion can provide technical support for the safety evaluation of the dam seepage of Donggu reservoir.