Abstract: The Pinghu Slope in the Xihu Sag of East China Sea Basin exhibits significant hydrocarbon exploration potential, characterized by strong heterogeneity in its enrichment patterns. Investigating the differential enrichment characteristics and their main controlling factors can offer a theoretical basis for oil and gas exploration in the Xihu Sag and similar areas. To this end, the study thoroughly examined typical hydrocarbon reservoirs and analyzed logging, seismic, and physical property testing data. It investigated the differences in enrichment and layer distribution of hydrocarbons in the Pinghu Slope and identified their influencing factors. The findings indicated a gradual decrease in hydrocarbon enrichment from the southern zone to the northern zone of the Pinghu Slope. Structural and lithologic as well as faulted anticline hydrocarbon reservoirs exhibited higher enrichment than faulted noses and fault block reservoirs. The hydrocarbon-enriched layers were classified into three types: multilayer enrichment in the Pinghu and Huagang formations, enrichment in the middle and upper sections of the Pinghu Formation, and enrichment in the lower and middle sections of the Pinghu Formation. The differential hydrocarbon enrichment in the study area was controlled by hydrocarbon supply distance, reservoir conditions, trap conditions, and fault sealing ability. Specifically, the hydrocarbon supply distance mainly controlled the differences in enrichment between different structural zones and reservoir types, while the differences in hydrocarbon enrichment between reservoirs of the same types were also influenced by reservoir conditions, trap conditions, and fault sealing ability. Shorter hydrocarbon supply distances, greater effective reservoir thicknesses, larger trap areas, and stronger fault sealing ability led to higher hydrocarbon enrichment. The vertical distribution of the hydrocarbon enrichment was influenced by fault transport capacity as well as fault and caprock configuration. When the fault's vertical transport capacity was robust and the residual sealing thickness exceeded the lower limit, hydrocarbons tended to accumulate in the middle and upper sections of the Pinghu Formation of the lower part of the regional caprock. In cases where the fault had a strong vertical transport capacity and had completely broken the caprock in the Pinghu Formation, hydrocarbons accumulated in both the Pinghu and Huagang formations. Conversely, when the fault transport capacity was weak, hydrocarbons mainly accumulated in the lower and middle sections of the Pinghu Formation. By focusing on the hydrocarbon supply distance, reservoir conditions, fault transport capacity, and fault and caprock configuration, this study provides a basis for determining the differences in hydrocarbon enrichment and identifying oil and gas enrichment strata in the Xihu Sag and similar areas.