Abstract:The Bitian ore deposit is a silver-dormnant large-、iie copper-gold-silver deposit related to Late Yanshanian subvolcanic rocks. Species of metallic deposits are quite complicated: Besides commonly-seen pyrite ,chalcopyrite and bornite, there exist varied copper-bismuth sulfosalt minerals(sandber}erite, Bi-tennantite, Bi-tetrahedrite, aikinite, wittichenite),tungsten-tin sulfides(mawsonite, kiddcreekite)and polymetallic sulfides. In addition to argentite, gold-silver minerals mainly include native gold, electrum, kiistelite and native silver of goldsilver series. These minerals were formed at bornite-chalcopyrite-pyrite Stacey gold-silver polymetallic sulfide stage and native silver-quartz stage respectively under differem physicochemical conditions. Most chalcopyrite, bornite, copper-bismuth sulfosalt minerals and tungsten-tin sulfides were formed under the conditions of medium-high temperature (260-380 ℃),relatively high sulfur fugacity(1gfs2=-8.74一-12.06),high salinity of fluids and boiling, whereas polymetallic sulfides and gold-silver minerals were formed under the conditions of medium-low temperature(120-260 ℃),comparatively low sulfur fugacity(lgffs2= -11 .6一-19.5)and also relatively low salinity of fluids. The discovery of varied types of copper-bismuth sulfosalt minerals indicates a certain defree of bismuth enrichment in the Bitian silver-dominant large-siie copper-gold-silver deposit. Therefore, importance should be attached to the study of the mode of ocurrence of bismuch.