Black organic- rich shale is the main source of shale oil and gas generation. It is the sedimentary product of reduced environment. During its formation, bacterial sulfate reduction (BSR) has an obvious effect on the water environment, but how BSR intensity affects the preservation of organic matter has not received much attention.Organic rich shale is widely developed in lacustrine basins in China, and the formation process is often accompanied by volcanic activities or transgression. A large amount of sulfates enter the lacustrine basin and change the sedimentary environment of the water body. Under different environments, BSR has significantly different effects on the preservation of organic matter in black shale.In this study, the shale of the Chang 7 member of Yanchang Formation in the Ordos Basin, the Qingshankou and the Nenjiang Formationsin the Songliao Basin were selected for study and compared with modern sediments.Studies have shown that the relationship between TOC and TS is complex, but the sulfate reduction index (SRI) and TOC show power exponential relation and two- stage changes.When SRI was greater than 1. 375, TOC as a whole was low, indicating that strong sulfate reduction consumed a large amount of organic matter.When SRI was less than 1. 375, TOC was significantly higher, indicating that the consumption of organic matter by weak sulfate reduction was relatively low, which was more conducive to the preservation of organic matter. Both volcanism and transgression provide a large amount of sulfate to water bodies, but there are significantly different results of the enrichment of organic matter in the lacustrine shale. The SRI of Chang 7 shale affected by volcanic activity was generally less than 1. 375, BSR had relatively weak organic matter consumption, and the TOC was high.However, the SRI of the bottom of 1st Member of the Qingshankou Formation and the bottom of 1st Member of the Nenjiang Formation was greater than 1. 375 under the influence of transgression, BSR overconsumed a large amount of organic matter, thus lowering the TOC. In the bottom of 1st Member of the Nenjiang Formation, the SRI was higher, indicating that the higher the transgression intensity is, the stronger the BSR reaction will be, which is not conducive to the preservation of organic matter.