CO2 geological utilization and storage (CGUS) is essential to realizing large-scale low-carbon utilization and carbon neutrality of fossil-based energy and industries. In order to overcome the key technical difficulties of large-scale emission reduction of this technology,it is crucial to identify and evaluate key technologies and equipment for CO2 geological utilization and storage. In this study,the various technologies of CGUS were defined and classified according to the expert panels and CGUS project investigations;and then the main characteristics and development trends of generic and special technologies were analyzed.The key technologies inventory was formed by the multiple criteria including unrepeatability,safety,efficiency,technical readiness levels(TRLs) gaps,and the development potential.Moreover,the site characterization and monitoring technology were classified and analyzed according to multiple criteria methods;finally,some strategic recommendations on research and development activities were suggested. As a result,the key technologies at the primary technology level mainly focus on site characterization and screening,risk assessment and management,site monitoring and early warning,CO2 utilization and resource treatment technology,synergies of carbon storage and resource recovery,etc. Although most of the technologies in China are at the stage of research and demonstration and the existing technology system can meet the requirement of large-scale CGUS projects;the significant technical gaps exist between TRLs in China and international levels in various key technologies. Moreover,breakthroughs are necessary for these immature technologies globally before large-scale implementation of CGUS technology. Site monitoring technology is vital technology related to the security and effectiveness of CGUS,and there are considerable gaps between the current technology readiness levels and the requirements of large-scale CGUS projects,which needs to be further developed and verified to adapt to the CO2 and reservoir environment,improve the long-term durability,monitoring accuracy,and the reliability of the interpretation of results. The key technologies requiring research and development include but are not limited to high-precision stratigraphic sequence exploration,high-precision seismic investigation technology,explanation of reservoir-seal pairs and lithology at ten-meter scales,assimilation technology of multiple data types and resolutions,site performance simulation and stratigraphic evaluation techniques,steering drilling & completion technology with related equipment,CO2-resistant downhole and surface equipment,integration of site monitoring technology system,CO2 geological storage risk prediction and risk management,underground space management and site performance assessment,collaborative optimization of carbon sequestration and resource recovery,etc. For the technical elements with large gap in technical maturity at home and abroad or highly dependent on imports such as high-precision sensors,CO2 resistant sealing material,downhole reagents,new structures,new algorithms and codes,and sustained-release agents,it is necessary to improve the gold content and added value of elements and narrow the gap with the international technical level. In macro research,it is necessary to deploy fossil-based energy and industrial emission reduction strategies,industrial planning research,source and sink matching,CCUS and multi-industry integration strategy,etc. Therefore,it is necessary to improve the TRLs of key technologies,improve the reliability and accuracy of existing technologies and technical elements,and ultimately set a solid foundation for core competitiveness in CGUS industrialization and commercialization.