Abstract: As the super and most petroliferous basin in China, Songliao Basin has achieved strategic breakthroughs in the exploration and evaluation of Gulong shale oil, of which the potential and scale of resources remain unclear. Based on the extensive geochemical data including total organic carbon (TOC), rock pyrolysis, vitrinite reflectance and pressure-reserved core, in combination with logging and production data, a systematic evaluation was conducted on various types of shale oil, primarily in Qijia-Gulong sag. A classification scheme using organic matter maturity and reservoir type as key indicators was developed for shale oil in Songliao Basin. As a result, grading standards for shale oil were established based on the key parameters such as TOC content, oil content, effective porosity, and oil saturation. A shale oil resource evaluation method was created, involving the key technologies such as precise evaluation of oil content, light hydrocarbon recovery and calibration of recoverable coefficient. Based on dynamic production data, the geological resource potential of shale oil under current technological conditions was assessed, achieving the predictive analysis of resource recoverability. The comprehensive evaluation indicates that Qijia-Gulong sag contains medium- to high-maturity shale oil resources of 107.73×10⁸t (including 42.08×10⁸t of Class Ⅰ resources and 33.67×10⁸t of Class Ⅱ resources), with technically recoverable resources exceeding 8×10⁸t. Additionally, the geological resources of dissolved gas are estimated to be 1.75×10¹²m³, and the technically recoverable resources amount to 0.13×10¹²m³. The resource evaluation results suggest that the favorable shale oil resources in Songliao Basin are mainly distributed in Qijia-Gulong sag, as being the essential strategic replacement resource. With future advancements in development technologies, the recoverable potential of shale oil is expected to increase significantly.