Abstract: Songliao Basin is one of China's major energy bases. With the implementation of the policy of revitalizing the old industrial bases in Northeast region, how to deal with the increase of CO₂ emissions arising from industrial and economic development has become an urgent problem. Performing CO₂ geological sequestration in this basin will be one of the major techniques to solve the problem. Therefore, with Songliao Basin as the study object and in consideration of the geological conditions of Songliao Basin, the authors selected indexes from the four aspects which include storage's size, storage's security, social environmental risk, economic suitability, and established an index system that includes 16 indicators by applying the gray relational analysis method to the basin level suitability assessment of the 33 Ⅱ tectonic units of Songliao Basin. The results provide a basis for target area selection of ground level.