Three typical near EWtrending crosssections of Changling fault depression in the Songliao basin were studied using the theory of balanced crosssections. The analysis indicates that rifting of the basin started in Huoshiling period and subsided intensively in Shahezi and Yincheng periods, with extension rates of 907.50 m/Ma, 1373.90 m/Ma, and 1100.00 m/Ma respectively, peaking at the Yincheng period. Structural shortening also took place at the end of the two extension periods, with a maximum and ratio of shortening 2.11 km and 2.89% in the former and 2.26 km and 3.21% in the latter. The basin started to transform from faulting depression to subsiding depression in Denglouku period, to postrifting cooling subsidence in ing the QuantouNenjiang period, characterized by weak extension, and to a stage of inverse structure development, characterized by compression at the end of the Nenjiang period. The Shahezi and Yingcheng Groups, as both major rock, and cover/reservoir rocks, formed a unique assemblage for authigenic and selfstoring hydrocarbon accumulation. Therefore, largescale lowmagnitude folding structure formed by tectonic activities at the end of Shahezi and Yincheng periods is a favorable zone for accumulation of oil and natural gas.