In　traditional　seismic　design　of　slope,　the　most　commonly　used　method　is　the　pseudo-static　method.　Because　of　its　limitations,　a　new　method　of　seismic　design　of　the　slope　is　proposed　based　on　the　strength　reduction　dynamic　analysis.　The　proposed　method　takes　into　account　the　interaction　between　the　supporting　structure　and　rock　soil　under　earthquake.　It　can　satisfy　the　design　requirements　of　earthquake　and　static　stability　of　slope.　The　internal　forces　of　supporting　structure　are　obtained　by　the　method.　So,　it　ensures　the　safety　and　economics　of　engineering　design.　The　seismic　design　of　high　slope　of　Mao　railway　station　demonstrates　the　feasibility　of　the　proposed　method　in　practice,　which　provides　a　new　idea　for　the　seismic　design　of　retaining　the　slope.