Abstract: Based on the design of Hanpingzui rockfill dam with concrete facing slab, the stresses and deformations of the dam body and impervious system are calculated by using the elastoplastic plane finite element method. According to the calculation results, the influences of the construction operation program, the length of the toe slab (connecting slab) and the rigidity of the diaphragm wall are compared. A rational design scheme for the impervious system of the rockfill dam is suggested after comprehensive analyses of all the influence factors.