Abstract: Abstract：The Jiyang depression is an important exploration target of the Shengli oilfield. The subsurface paleotemperature was an important factor for affecting the formation and evolution of sedimentary basins and the determination of subsurface paleotemperatures has great significance for the study of the hydrocarbon generation history and entrapment history. There are many methods for the study of subsurface paleotemperatures, of which the use of “the past as the key to the present”and geothermometry are the main methods. In this study the crystallinity of authigenic illite and chemical composition of authigenic chlorite was used to analyze the Cenozoic paleogeothermal gradients in the study area. The study indicates that the Cenozoic paleogeothermal gradients in the Jiyang depression were 37.2-38.2°C/km. This understanding is of great significance for the study, exploration and evaluation of the petroleum geology of the Jiyang depression.