Abstract: It is an effective means to set artificial boundary by adopting 3D finite element technology to carry out seismic analysis of complex soil conditions. This paper is to realize the setup of artificial viscoelastic boundary as well as the exertion of equivalent load by applying Fortran to developing interface program. The availability of artificial viscoelastic boundary and wave input is verified through numerical calculation, and both the efficiency and precision are rather satisfactory. If apply this program to certain NPP seismic analysis of complex soil conditions, and compare the calculation result with that of the general program.