Abstract: In order to optimize the economic cost of anti-seepage system,this paper studies the influence of anti-seepage curtain size param‐eters and dam foundation parameters on dam seepage.By taking a deep overburden rockfill dam in Xinjiang as an example,the seepage mod‐el is established by self-programmed quasi-three-dimensional seepage analysis program.By using the sensitivity analysis method of progres‐sive discrimination,a sensitivity analysis is carried out on the depth H of impervious curtain,thickness D of impervious curtain,permeabili‐ty coefficient K_a of impervious curtain,permeability coefficient K_b of foundation and permeability coefficient K_c of transition zone,and the sensitivity order of each parameter is determined.Example analysis shows that H,K_a,K_b are more sensitive to the seepage flow rate of single width,and H,K_c are more sensitive to the seepage gradient of anti-seepage curtain.The significance level of parameter sensitivity is given quantitatively to improve the accuracy and reliability of sensitivity analysis,which can serve as a basis for a seepage analysis of the face rockfill dam on deep overburden.