Abstract: Steep slope belt of Langgu Depression has a large set of conglomerate body deposit developed along the declining disc of Daxing fault. From the south to the north, the deposit is divided Gu?an conglomerate group, Jiuzhou conglomerate group, and Caiyu-Fengheying conglomerate group. Drilling of Daxing conglomerate body has an active oil and gas show. It is an important exploration field. However, the physical properties of most conglomerate body reservoirs are poor with undesirable exploration results. Based on the differential analysis of Daxing fault in the areas of times of activity, style of structural activity, conditions of physical sources and oil sourcing window of conglomerate bodies, it is assumed that difference in times of activity for Daxing fault not only influences the scale and physical sources of conglomerate bodies but also the quality of conglomerate body reservoirs. The difference of Daxing fault tectonic style reflects conglomerates body deposits of different types. The lithology of mother rock and the difference in late diagenetic compactness determine distribution of high-quality conglomerate reservoirs. Conglomerate bodies and their contact surface with the surrounding source rock determine the differential in oil sourcing window in space and control the scale of conglomerate body reservoirs at the same time.