Abstract: The Shales developed in continental rifted lacustrine basins in eastern China have demonstrated promising shale oil exploration potential. However, influenced by multi-provenance inputs, these shales exhibit complex lithofacies and significant heterogeneity in shale oil accumulation. This study investigates the 3rd lower sub-member of Shahejie Formation in the Gubei Sag, Bohai Bay Basin, aiming to unravel the developmental patterns of shale lithofacies under multi-provenance conditions and elucidate differential shale oil enrichment across lithofacies, thereby evaluating resource potential. Key findings reveal that the clay-rich hybrid shale lithofacies exhibits optimal oil content, attributable to high organic matter abundance, dominance of Type I kerogen, and a well-developed micropore-fracture network formed by oriented arrangement of illite/smectite mixed layers, coupled with high hydrocarbon retention efficiency. The carbonate-rich and felsic-rich hybrid shale lithofacies display moderate oil content. In contrast, the felsic-carbonate shale lithofacies, despite possessing the highest brittleness index, shows the lowest organic matter abundance and oil content. Reservoir spaces across lithofacies are dominated by micron-scale dissolution pores, inter-crystalline pores, and clay interlayer fractures. Crucially, the predominant orientation of high-conductivity fractures aligns with the present-day maximum horizontal principal stress, significantly enhancing the potential for generating complex fracture networks during hydraulic fracturing. Integrated analysis of crude oil properties (light-medium oil) and over-pressured zone distribution identifies the eastern subsag and northern central uplift within the study area as shale oil enrichment "sweet spots". These results not only guide exploration deployment in the Gubei Sag but also provide critical theoretical insights for shale oil exploration in analogous continental rift lacustrine basins with strong multi-provenance inputs.