Abstract: The Songnan Gas Field is located in the high position of the Yaoyingtai deep buried structure,which is situated in the Daerhan faulted bump, the central uplift belt in the faulted depression of Changling in Southern Songliao Basin. Through analyzing the characteristics of hydrocarbon source rocks and transportation systems, it is believed that the gas accumulation in Denglouku and Quantou Formation in the Songnan Gas Field is characteried by two-way hydrocarbon supply. The Daerhan fault is the main fault which controlled the scale of the gas reservoirs. The open and close of the Daerhan fault controlled the preservation and destruction of the gas reservoirs. On the basis of analyzing results on gas reservoirs and hydrocarbon accumulation conditions, it is conclued that hydrocarbon accumulation was due to multi-phase of hydrocarbon generation, hydrocarbon supply from northern and western depression, short distance hydrocarbon migration, and excellent matching between reservoirs and seal rocks.