Ankerite microclinite, a special type of rock, is closely related to the ore-forming process of massive sulfide deposits in the East Liaoning Proterozoic rift. Assuming rhythmic layering form, the rock is rich in K,B and Si and falls into the field of hot water deposition both in Al2O3-SiO2-(CaO MgO) diagram and in Fe-Mn-(Cu Ni Co) diagram. Its REE geochemistry is characterized by negative Ce anomaly and enrichment of LREE, and its Si isotopic geochemistry implies an origin of hot water deposition. As a sort of hot water sedimentary rock, it exhibits important ore-prospecting indicator significance. With this rock as an indicator, sulfide orebodies were discovered on the outskirts of the old mine.