One new record species of genus Leucoagaricus is reported from China: Leucoagaricus tener(P.D.OrtonBon. Materials were collected from Leiwuqi County, Tibetan Autonomous Region. It is characterized by its deep gray-brownish squamules,ellipsoid basidiospores,subcylindrical,narrowly clavate or fusiform cheilocystidia,trichodermial palisade made up of undifferentiated elements,and clamp-connections absent.