Abstract: Recent studies have indicated that the feedback control is an important factor influencing the results of hydrocarbon expulsion of coal. Based on the principle of system theory and simulation methods, a model for the system dynamics of hydrocarbon expulsion of coal is built, which includes three subsystems of paleo-pressure, saturation of hydrocarbon and process of hydrocarbon expulsion. A program based on the new model is designed and used to study the characteristics of hydrocarbon expulsion of coal in the Rongxintun region of the East Liaohe basin. Results of this study proved that the model could be applied to solve many problems, such as feedback control and non-linear features of hydrocarbon expulsion.