Abstract: In 2015 the old code Specification for seismic design of hydraulic structures was revised into a new code, Code for seismic design of hydraulic structures of hydropower projects. In this study, we have investigated dynamic responses and anti-seismic stability of a typical concrete faced rockfill dam (CFRD) of 250 m high under two types of seismic excitation formulated according to the new and old codes separately, to examine the differences caused by the two excitations. Our FEM results indicate that relative to the old code, the dynamic responses to the seismic waves designed by the new code are increased considerably and the local stability of dam slope is lowered accordingly. Thus we suggest more attention to these differences and a safety re-check on the built dams when it is possible.