Intrusive rocks are widely distributed in Cretaceous sedimentary strata of the central and northern Fuxin basin. The petrological characteristics and spatial distribution of intrusive rocks in this area and their formation age, as well as the influence of the abnormal high temperature brought by intrusive rocks on the hydrocarbon generation and evolution of source rocks are still unclear. Petrology, geophysical logging, organic geochemistry, isotope chronology methods are used in this study to explore the intrusive characteristics of Cenozoic diabase and its petroleum geological significance in the central and northern Fuxin basin. The results show that the intrusive rocks in this study area are mainly diabase, and the main minerals are basic plagioclase and pyroxene, which have typical ophitic textures. Diabase has the logging response characteristics of low gamma and acoustic time difference, high resistivity and density, and its spatial distribution forms are mainly dykes and sills. Drilling data show that the diabase intrusion has the characteristics of deep intrusion and large thickness in the east but shallow intrusion and smaller thickness in the west. The plane distribution is closely related to the main northeast- trending faults, and presents three scattered intermittently connected northeast- trending bands. Apatite U- Pb isotope dating of a diabase sample in the Yaotuhulu area of Fuxin basin, yields an age of 33. 75±1. 83 Ma indicating the period of the early Paleogene Oligocene. In addition, the abnormally high temperature brought about by diabase intrusion can significantly reduce the hydrocarbon generation depth of source rocks, and promote the maturity of source rocks (Ro up to 2. 32%), thereby promoting the hydrocarbon generation potential of source rocks and reducing their organic matter abundance. In general, the diabase have thermal aureole thicknesses on the upper surrounding sediments of 0. 8～1. 7 times its own intrusive thickness, and the influence range of the lower surrounding sediments is about 0. 9～1. 5 times its own thickness. Therefore, the widely distributed diabase in the Fuxin basin is the product of magmatic activity under the Paleogene Eocene regional extensional setting, and they have an important influence on the secondary hydrocarbon generation of source rocks.