In the deep Paleogene of graben basins in eastern China, not only the tight sandstone oil and gas resources, but also the secondary hydrocarbon generation of source rocks are universal and worth studying. In order to elucidate the laws of oil and gas accumulations in tight sandstone with different phases and explore the diversity of its genetic mechanism, Shahejie Formation in Wendong area was taken as an example in this paper to carry out further research. Firstly, the differential enrichment rules of oil and gas reservoirs are clarified from the aspects of spatial distribution, phase type and fluid properties. Secondly, the reasons for differential accumulation of oil and gas reservoirs were analyzed from multiple perspectives by using a variety of methods, such as source rock thermal evolution simulation, fault activity evaluation and reservoir porosity evolution. A large number of researches have been carried out on hydrocarbon generation and expulsion process of source rocks, paleo-temperature and paleo-pressure changes, the connectivity of skeleton sand bodies, reservoir physical property and densification process, tectonic strength and so on. The results indicate that the deep tight sandstone reservoirs of the Paleogene in the Wendong area have a quasi-continuous distribution characteristic of "planar partition and longitudinal zoning". Secondary kerogen cracking gas, crude oil cracking gas, medium light crude oil, and primary kerogen cracking gas are distributed in a semi-circular manner, from the center of Qianliyuan Sag to Wendong graben and rollover anticline belt at the high structural position. In conclusion, the two periods of hydrocarbon generation and expulsion of source rocks lead to the discontinuity of hydrocarbon accumulation process. Paleo-temperature and paleo-pressure conditions control the phase types of hydrocarbon filling. The lateral connectivity and the difference of physical properties of the skeleton sand bodies limit the distribution range of oil and gas reservoirs. The temporal and spatial availability of faults during the critical accumulation period determines the differential enrichment of oil and gas. The temporal and spatial validity of faults during the critical accumulation period determines the extent of differential enrichment of oil and gas.