The Permian reefal limestones are widely distributed in Changshitou Mountains, Maduo Coun- ty, Qinghai Province. Previous investigators have classified this area as part of the A'nyemaqen strati- graphic region, largely on the basis of the absence of fusulinid fossils in this area. Our study has recovered a large amount of fusulinids in Permian reefal limestone in this area, including 11 genera and 19 species. Two fusulinid zones have been recognized, including the Parafusulina zone and the overlying Neoschwa- gerina margaritae zone, suggesting that the fossiliferous reefal limestones are of the Gufeng Stage, Maok- ou Series, middle Permian System. The fusulinid assemblages can be compared with contemporaneous fusulinids in South China. On the basis of this correlation, we propose that the Changshitou Mountains ar- ea is part of the Tethyan Province in the middle Permian. According to the composition of the fusulinid as- semblages, the Shuweimenke Formation reefal limestone should be classified in as part of the Bayan Har palaeobiogeographic division.