To　assess　the　seismic　behaviors　of　vast　brick　masonry　buildings　with　periphery　beams　and　constructional　columns　in　current　China,　three　performance　levels,　i.　e.,　nearly　intact,　moderate　damage　and　serious　damage　are　given　on　the　basis　of　performance-based　seismic　design　codes　at　home　and　abroad.　In　view　of　seismic　experimental　data　from　54　walls,　the　ranges　of　inter-story　drift　ratio　are　obtained　for　three　different　seismic　performance　levels.　The　seismic　performance　indices　and　seismic　assessment　method　are　proposed　e-ventually,　and　a　5-story　brick　masonry　building　is　evaluated　by　the　proposed　method.　The　results　show　that　the　maximum　inter-story　drift　ratio　with　the　value　of　1/387　occurs　at　the　third　story　of　the　lateral　wall　under　large　earthquake,　not　collapsing　due　to　the　large　drift.　However,　the　building　damages　seriously　when　the　inter-story　drift　ratio　is　nearly　to　the　limit　value　of　1/350.　This　implies　that　the　allowable　drift　value　and　assessment　method　proposed　by　authors　are　applicable　and　effective　for　assessing　the　seismic　performance　of　brick　masonry　buildings.