Abstract: K-feldspar leuco-granulitite in Precambrian metamorphic rock series is not quite thick, but the stratigraphic horizon of its exposure is persistent and its areal extent is wide. This paper preliminarily summarizes its field features, mineral composition and chemical composition, and considers that it is a kind of typical metasedimentary rock. Therefore the author suggests that the K-feldspar leuco-granulitite may serve as one of the key beds of the Precambrian metamorphic rock series.