Abstract: An open system with programming temperature raising apparatus is used in this simulation experiment of thermal evolution of organic matters. Based on experiment results, a deep research on the thermal evolution of Permo-Carboniferous coal in the south slope of Huimin Sag has been conducted. The gas generation model is established and the influence factor of the second gas generation potential is discussed. This work gives a base for evaluation of resources potential and calculation of resources, and this work will also direct the exploration in similar area such as the other parts of Bohai Bay Basin.