The mineral composition, major and trace elements, carbon and oxygen isotopes were used to analyze the lithofacies type, as well as sedimentary environments of different lithofacies and their relationship with organic matter accumulation in the Niutitang black shale from the well ZX in Zhenyuan County, northern Guizhou area. The results show that the lower member of Niutitang Formation is mainly composed of siliceous shale with TOC of 4.96%~10.1%, and the upper member is mainly composed of mud- rich siliceous shale with TOC of 1.43%~9.04%. Even though both siliceous shale and mud- rich siliceous shale were deposited in a reducing environment, the sedimentary environment of siliceous shale was more reductive than that of the mud- rich siliceous shale. In this study area, oxygen- deficient reducing environment has a stronger influence on organic matter enrichment than hydrothermal action and terrigenous detrital content.