The improved node virtual flow method is used to solve unconfined seepage field; and the damage vertical flow behavior is simulated by zero thickness crack model; and then the finite element method of crack seepage problem of the concrete faced rockfill dam (CFRD) is obtained. Based on a CFRD

the program composition with Fortran was used to calculate the 3D seepage field under the failure condition of the single or more than one vertical fracture of concrete slab; and the water head distribution

saturation line and leakage are obtained; and then the rules and characteristics of unconfined seepage field are analyzed. The results show that the method can accurately position exit point and saturation line of seepage field of CFRD

and well simulate seepage field in dam area under the failure condition of vertical fracture of concrete slab so as to provide reference for concrete face jointing design of CFRD.