Based on relatively plentiful temperature data, the characteristics of present geothermal field in southern area of the North China Craton are studied systematically, and the controlled factors of the present geothermal field as well as its effect on hydrocarbon generation of the Paleozoic source rocks are discussed. It is showed that the present geothermal gradient and heat flow are 269 ℃/100m and 5654 mW/m2 , the geothermal field in the northern and eastern areas are higher than the south and west. The geothermal field of studied area belongs to the transitional type between the hot basin in eastern and cold basin in western China. The present geothermal field is controlled by thickness of lithosphere, structural features as well as groundwater activity. Different areas have the different thermal evolution processes and results. The present geothermal temperature is considered as the higher compared with its paleotemperature in the middle areas of Zhoukou depression and Kaifeng depression, which play an important role in Paleozoic hydrocarbon generation. However, the present geothermal temperature is lower than paleotemperature in other areas, and the paleogeothermal field is the key factor for the Paleozoic hydrocarbon generation of the Paleozoic source rock.