Abstract: The subsurface in-situ converted shale oil has huge resource potential, and it is a strategic potential resource for China’s oil and gas. Based on the theory of hydrocarbon generation and the principle of chemical kinetics, this paper proposes an evaluation model for the resource potential of in-situ converted shale oil, and derives an estimation model of organic porosity after in-situ conversion of shale. Through the research of key parameters, in combination with experimental analysis, it is obtained that the remaining hydrocarbon potential after in-situ conversion of the 7th oil layer of Yanchang Formation (Chang-7 oil layer) shale ranges from 79.92 mg/g to 197.78 mg/g, with an average of 134.67 mg/g, in the evaluation area of Ordos Basin. The oil-gas ratio of the conversion product is 7 to 3. The results indicate the following. (1) The core area of in-situ converted shale oil in the Chang-7 oil layer is 16 932 km², and the total resource equivalent of converted shale oil is 494.0×10⁸t, of which there are 345.8×10⁸t of liquid hydrocarbon and 148.2×10⁸t of gaseous hydrocarbon (oil equivalent). The total producible reserves are 321.1×10⁸t after conversion based on the 65 % empirical recoverable coefficient. (2) The average newly-increased organic porosity in the core of study area is 5.9 % , and the maximum can reach 17.9 % . (3) The sweet spot is mainly distributed in the east of Zhengning area, the east of Huanxian area and the vicinity of Qingcheng area in Ordos Basin. The research method can provide a reference for the resource potential assessment of in-situ converted shale oil and the field pilot test of shale oil in the Chang-7 oil layer.