The Huize and Maoping deposits, the famous highgrade Mississippi Valleytype leadzinc deposits in China, are located in the central south of the SichuanYunnanGuizhou leadzinc polymetallic ore cluster area in the southwestern margin of the Yangtze block and tectonically in structural composite area of Xiaojiang fault zone, ZhaotongQujing hidden fault zone, and Yadu Ziyun fault zone. This study discussed effect of sulfate evaporate salt layer on leadzinc mineralization of the Huize and Maoping deposits using sulfur isotope compositions of sulfides and gypsum from the two deposits. δ34SVCDT value of the Huize ore sulfides ranges from 11.0‰ to 20.0‰ (averaging 14.7‰), with most concentrated in 13.0‰~17.0‰, roughly representing total sulfur isotopic composition. δ34SVCDT value of the carbonate associated sulfate ranges from 10.4‰ to 18.6‰ (averaging 13.1‰),slightly lower than the ore sulfides. δ34SVCDT value of the gypsum in the Carboniferous gypsum salt layer ranges from 12.9‰ to 17.1‰ (averaging 13.6‰), which is consistent with that of the carbonateassociated sulfate. δ34SVCDT value of the ore sulfides in the Maoping deposit is closely related to its occurrence layers. The δ34SVCDT value of the ore sulfides in the Baizuo Formation (C1b) ranges from 7.1‰ to 17.5‰，with an average of 12.8‰, which is slightly lower than carbonateassociated sulfate and gypsum in Carboniferous carbonate strata. The δ34SVCDT value of ore sulfides in the Zaige Formation (D3zg) ranges from 18.3‰ to 22.7‰, with an average of 21.1‰. The results are unlikely with the ore sulfides in the Baizuo Formation (C1b) or the Huize deposit. The δ34SVCDT value of the gypsum in the Zaige Formation (D3zg) ranges from 21.9‰ to 25.9‰, with an average of 23.6‰, which is slightly higher than sulfides in the Zaige Formation (D3zg). By comparing the sulfur isotopic compositions of the sulfides, sulfate and gypsum, we propose that the sulfur in the ore sulfides of Huize and Maoping lead zinc deposits mainly came from the sulfate in the ore bearing strata. In addition, sulfur in the ore sulfides of the Huize lead zinc deposit mainly came from Carboniferous gypsum salt layer, with only 10% of the sulfur from the underlying Zaige Formation gypsum salt layer; while sulfur in the Zaige Formation ore sulfides of Maoping lead zinc deposit derived from the Zaige Formation gypsum salt layer, sulfur in the Baizuo Formation ore body mainly came from the Baizuo Formation gypsum salt layer, i e. the gypsum was reduced in situ. Collectively，we divided the metallogenic process into two stages. At the first stage, gypsum reacted with methane and/or other organic compositions forming hydrogen sulfide gas, which preserved in interlayer fissures or karst caves companied with large scale dolomization. At the second stage, ore forming fluids containing Pb, Zn and other metals leached from the basement rocks mixed with H2Srich fluids, resulting in precipitation of pyrite, galena, sphalerite and forming high grade ores.