Abstract: Carbon emission reduction of traditional resources such as coal plays a decisive role in achieving the goal of “carbon neutralization”. Under the policy background of “double carbon” and “coal de productivity”, CO₂ geological storage system study in coal seam development area has a distinct era background and practical basis. Taking the CO₂ geological storage system in the coal seam development area as the research object, development area can be divided into two areas, including mined area and untapped area. The geological storage principle and research status of three storage spaces of goaf, coal seam and salt water layer are clarified from the aspects of CO₂ phase state transformation, CO₂ storage capacity and geological capping conditions. Based on the theories of material mechanics, coalbed methane geology, the applicability of low-temperature freezing and thawing, acoustic (microwave) antireflection, hydraulic fracturing and other technologies in the field of CO₂ enhanced storage are discussed, and the urgent attention direction of different storage modes is clarified. On this basis, the application prospect of CO₂ step-by-step combined geological storage model in mined and untapped areas are studied. The applicability evaluation method of CO₂ geological storage in coal seam development area is put forward under the consideration of single storage and step-by-step joint storage.