Abstract: The Middle Jurassic Lianggaoshan Formation in the Fuling area of the Sichuan Basin represents a continental lacustrine basin characterized by complex lithology and strong heterogeneity. The Lianggaoshan Formation, as an important shale oil and gas-producing layer of continental lacustrine basin, requires clarification of its lithofacies characteristics and the evolution process of the sedimentary environment. Taking the lower submember of Member 2 of the Lianggaoshan Formation in the Fuling area as the research object, this study integrates TY1 core observations, logging, data, thin section, paleontological and geochemical indicators to classify lithofacies. Combined with regional drilling data, lithofacies characteristics and transverse correlation research are carried out in the study area to reconstruct the sedimentary environment, identify favorable reservoir development intervals, and analyze its oil and gas geological significance. Eight lithofacies types were identified using the "three-terminal" naming method, including: gray massive sandstone, grayish-white dense shelly limestone, gray sand-laminated siltstone, dark gray low-carbon silty shelly laminated mixed shale, gray to dark gray liquefied deformed sand mudstone interbedded, grayish black medium carbonaceous silt-laminated clay shale, grayish black rich carbonaceous silt-laminated clay shale, dark gray medium carbonaceous silt-laminated clay shale. Lacustrine facies develop in the lower submember of Member 2 of the Lianggaoshan Formation, which can be divided into two sub-facies, shallow lake and semi-deep lake, and can be further subdivided into five sedimentary microfacies. Microfacies characteristics and trace element analysis indicate a warm and humid, paleoclimate and an oxidized to sub-reduced water environment with low salinity. Paleoproductivity was highest in layers ②, ③ (transitional segment), ④ (mud shale), and layers ⑥, ⑦, and ⑧. Member 2 of the Lianggaoshan Formation records a stage of lake encroachment and water expansion, reaching maximum depth and lateral extent in the middle to lower layer mud shale, where thick, continuous shale developed, favorable for hydrocarbon accumulation. Thus, the lower submember of Member 2 of the Lianggaoshan Formation is conducive to shale oil and gas enrichment and is a favorable interval for shale reservoir exploration in the Lianggaoshan Formation.