Abstract: Mafic rocks are exposed in northern Anhui Province. It consists of diabase, gabbro-diabase and diabase-porphyrite, and the minerals mainly include clinopyroxene, plagioclase, hornblende and Ti-Fe oxides. In this paper, clinopyroxene and ilmenite were studied in detail using microprobe. An analysis of clinopyroxenes shows that the end members are composed of wollastonite, enstatite and ferrosilite, belonging to augite. Calculation results and chemical analysis of ratios probably indicate that the fractional crystallizing products were formed by the relatively primary magma in shallower magma chambers. The crystallizing temperature of the clinopyroxenes are 1109~1206℃ and the highest pressure is 0.6 GPa, suggesting the depth of 19.8km. The ilmenite in Lan'gan area has low MgO and MnO, high FeO, and very low Cr₂O₃. The mineral characteristics of clinopyroxen and ilmenite are different from features of the index minerals in typical kimberlite.