The alkali reactivities of different various compositions and textures of basaltic aggregate are studied by the petrography method, accelerated mortar-bar test method and concrete prism method.The test samples for adopting accelerated mortar-bar test are analysed by the SEM and the energy dispersive X-ray analy sis(EDXA). The experiment indicates that the basalts containing chalcedony and microcrystalline quartz possess potential alkali reactivity and belong to typical alkali-silica reaction.