The lacustrine dark shale deposits of the Upper Cretaceous Qingshankou Formation in the Central Depression of Songliao Basin contain a considerable amount of shale oil resources, among which the shale oil exploration of the Qingshankou Formation in the Qijia-Gulong Sag has made a major breakthrough. In this paper, methods of sealed thermal release, combined with organic solvent extract and Rock-Eval, has been used for the comprehensive evaluation of shale oil-bearing capacity of the Qingshankou Formation. The TOC of shales from the Qingshankou Formation in the study area range from 1.48% to 6.97% with an average value of 3.40%. The values of Tmax range from 440 ℃ to 453 ℃ with an average of 448 ℃ for the samples after extraction, and the production index ranges from 0.28 to 0.67, indicating a middle stage of oil generation window. The shale oil contents of the studied samples range from 4.00 mg/g to 19.49 mg/g with an average value of 13.74 mg/g. The contents of free oil range from 3.41 mg/g to 13.63 mg/g with an average value of 8.70 mg/g; while the content of adsorbed oil ranges from 0.60 mg/g to 9.43 mg/g with an average value of 5.04 mg/g. Free oil is made up of restricted oil and movable oil in the proportion of 1∶1. The content of restricted oil of the studied samples ranges from 1.81 mg/g to 8.49 mg/g with an average of 4.15 mg/g; while the content of movable oil ranges from 1.36 mg/g to 11.05 mg/g with an average of 4.55 mg/g. The movable oil resource is 12 kg/m3 based on the average content of mobile oil, which reveals good resource potential of movable shale oil in the first member of Qing-shankou Formation of the Sanzhao Sag.