Abstract: Pb-Zn ore has been listed as a favorable mineral in Western Hunan and Eastern Guizhou, with large reserve, long development history and huge potential. Through comprehensively analyzing the previous bioherm data of Western Hunan and Eastern Guizhou, the authors introduced the sedimentary characteristics of algal limestone, and discussed the ore-controlling mechanism of algal limestone based on a series of geological data. The results show that the ore-forming materials are mainly derived from the absorption of Pb²⁺ and Zn²⁺ ions by algae and carbonate mud. The genesis of the deposit belongs to sedimentary deposit type, which has the characteristics of the post diagenetic stage. The junctions between algal reef limestone and different lithology and the nearby micro geochemical barrier zone are often rich in Pb-Zn ore body. The cross shape area at the point of contact between algal reef limestone and thin argillaceous dolomitic limestone in reef channel, is often rich in Pb-Zn ore body too. Pb-Zn rich bonanza mainly occurs in Qingxudong Formation limestone and is obviously controlled by the algal reef limestone. To meet the increasing needs of Pb-Zn ore at home and abroad, a further study of the controlling factors and enrichment law of stratigraphic lithofacies has important practical significance in guiding ore prospecting in this region.