Abstract: In recent years, the concept of petroleum systems has got wide attention. It provides a new research method for hydrocarbon exploration. Based on the thermal-evolution profile stuey of organic matter in the hydrocarbon source rock of the Dehui Depression in the Songliao Basin and the thorough collection and collation of drilling, logging, seismic and testing data from the working area, the history of hydrocarbon generation and expulsion was dynamically simulated. According to the laser Raman spectrum analysis of organic inclusions, the correlation of hydrocarbon sources and the abnormal pressure of the strata, the Dehui Depression can preliminarily be divided into two petroleum systems on the deep profile, that is, the lower else-sourced petroleum system which is bounded by the abnormal pressure interface or unconformity plane on the top of the Yingcheng Formation and the upper else-sourced petroleum system which is bounded by the abnormal pressure surface on the top of the Quansan Formation. On the plane, Nongan, Baojia and Buhai three petroleum subsystems were divided. Among them, Nongan petroleum subsystem is the most favorable one, Baojia petroleum subsystem is the second, and Buhai petroleum subsystem takes the third. Otherwise, the lack of the method was pointed out.