Objectives: The Da’anzhai Member of Lower Jurassic Ziliujing Formation is one of the main producing reservoir of tight oil in Sichuan Basin. It contains abundant oil and gas resources and has been producing steadily for several decades in the central Sichuan basin. However, the Da’anzhai Member of the eastern Sichuan area has not made a breakthrough and the corresponding research is relatively low. Sedimentary environments of sub- facies are analyzed according to the petrological characteristics and longitudinal combination characteristics of rock. Based on the field outcrop measurement and regional data, the lacustrine sedimentary facies model of the Da’anzhai Member in the northeastern Sichuan Basin is established. Methods:The petrological characteristics and longitudinal combination characteristics of rock in field were studied through the outcrop observation and microscope analysis. In this paper, the sedimentary environment is studied based on the petrological characteristics and geological background, and the sedimentary model is established. Results:The results indicate that the Da’anzhai Member in the study area is characterized by a mixture of lacustrine carbonate rocks and terrigenous clastic rocks. The coquina limestone is mainly developed in the First and Third Sub- members, and mudstone(shale) is developed in large numbers in the Second Sub- member, and siltstone is mainly distributed in transition layer and the top of the First Sub- member. The sedimentary subfacies of the Da’anzhai Member in the study area include the shore lake subfacies, shallow lake subfacies, slope subfacies and half deep—deep lake subfacies. Among them, shallow lake subfacies can be divided into shell shoal microfacies, shallow lake mud microfacies and sandy shallow microfacies, and lake slope subfacies can be divided into slope mud microfacies and storm microfacies. The range of shell particle size is large and the types of shell are various, including bivalves, ostracoda, gastropods and charophyta in the coquina limestone in the First Sub- member. In the Second Sub- member, there is high content of shell in coquina limestone, and shell type is single, mainly bivalves. Conclusion: WTBZ〗Based on the results from the analysis and arrangement for the collected data. The results show that ① in the lower Jurassic Da’anzhai Member of the study area, lacustrine carbonate and mudstone(shale) are mainly developed, including biological limestone, crystalline limestone, micrite limestone, mudstone(shale) and silt—fine sandstone. ② From the shore to the lake, subfacies can be divided into shore lake subfacies, shallow lake subfacies, slope subfacies, and half deep—deep lake subfacies. And the study established the sedimentary facies model of the area. ③ Favorable reservoirs are mainly shell shoal microfacies in shallow lake subfacies and storm microfacies in slope subfacies developed.