Carbon Capture, Utilization, and Storage (CCUS) is central to achieving carbon neutrality, with CO2 geological storage serving as a key negative-emission pathway. Although extensive research has addressed storage mechanisms and monitoring tools, the site-specific applicability of these techniques and the trade-off between storage security and cost remain insufficiently constrained. This review synthesizes peer-reviewed literature, international databases, and Chinese field reports to assess recent technical progress from an engineering perspective focused on China. Six storage types are compared, namely, deep saline aquifers, depleted oil/gas reservoirs, coal seams, basalts, shales, and marine sediments, using technical and economic criteria. Four trapping mechanisms, including structural, residual, solubility, and mineral trapping, are analyzed in terms of their time-dependent evolution and uncertainty ranges, with particular emphasis on the reaction kinetics of supercritical versus dissolved CO2 injection in basalt. For monitoring technologies, integrated systems are compared functionally, and the resolution-cost trade-offs that affect field deployment are discussed. The synergies and conflicts of CO2-enhanced oil recovery (CO2-EOR) are also examined, focusing on net climate benefit, lifecycle emissions, and the policy dilemma of producing additional hydrocarbons. Five priority areas are identified for future research, including multi-scale coupled simulation, intelligent monitoring networks, storage-utilization synergy optimization, marine storage pathway clarification, and post-closure liability frameworks. This review is intended to serve as a practical, technically grounded reference for CCUS engineering deployment in China.