Abstract: The sedimentary environments of the ore-bearing strata within the Yingmusi lead-zinc deposit are discussed exemplified by the Yingjiagou section. The ore-bearing strata consist significantly of organic reef facies rocks. The ore deposit was formed by the multistage upward flowing,metasomatism and precipitation of the ore-bearing hydrothermal brines in the rocks of the reef-cap facies. The reefal rocks are considered to be the favourable locus for the metasomatism and precipitation of the ore-bearing hydrothermal brines.