The eastern marginal zone of Sichuan Basin is a key area for shale gas exploration in the Longmaxi Formation in southern China. The first large- scale shale gas field in China has been established in the Fuling area. The original geological conditions of shale gas are superior in the study area. Due to the later strong tectonic superpositioning and reworking, the preservation conditions are very complex, which directly affect the degree of shale gas enrichment. Other than Fuling area, no major breakthrough has been achieved in productivity construction. Methods: Using drilling, field investigations, logging, seismic, and analytical test data, the effects of structural and evolutionary characteristics, uplift and denudation, structural styles, faults, and fractures on shale gas enrichment in the study area were analyzed. Combining with regional indirect and direct cap rocks and floor conditions, formation pressure, gas content, test yield, et al., the preservation conditions and discriminant indicators of the study area were analyzed. Results: The study concluded that: the areas with a positive tectonic background, a gentle stratum, a moderate burial depth, a relatively late uplift and erosion time are conducive to the accumulation of shale gas; underdeveloped faults and good sealing property of faults, and the further away from the denuded area or basin- controlling faults, are more conducive to the preservation of shale gas; regional indirect cap rocks, especially the development of gypsum salts, good direct cap rocks and floor conditions are important factors for the preservation of shale gas; the formation pressure coefficient, over 1.5 on average, within the Sichuan Basin is high, which presents the good preservation conditions and the shale gas highly enrichment; the formation pressure coefficients gradually decrease and the preservation conditions gradually become worse from the margin of the basin to the outside, which is not conducive to the enrichment of shale gas. Conclusions: Comprehensive evaluation considers that the marginal zone close to the inner side of the eastern Sichuan Basin is a type Ⅰ preservation zone, the anticlines with high and steep inclination angles in the basin, the slope along the margin of the basin, and the residual syncline zone outside the basin are type Ⅱ preservation zones, and the transitional areas between the synclines and anticlines are type Ⅲ preservation zones.