Abstract: Palaeogeothermal gradients during various geological times in North China are determined based on palaeogeothermal restored by using vitrinite reflectance data and combining with geologic history. The palaeogeothermal field in North China went through a evolutionary process from low to high and then to low again. The paleozoic source rock in North China went into the main oil generating period at the end of Triassic.