Abstract: Metal materials are widely used in key industrial sectors such as energy and chemical engineering, but the severe threat of stress corrosion cracking(SCC) significantly restricts the safe operation of equipment. The latest research progress on the mechanisms, propagation modes, and protection technologies of stress corrosion cracking were systematically reviewed. It elucidated the competitive mechanisms of anodic dissolution and hydrogen embrittlement, as well as the propagation laws of transgranular/intergranular cracks, under the coupled effects of environment, stress, and materials. The regulatory roles of grain boundary characteristics and local stress fields on crack paths were revealed, and the synergistic protection mechanisms of alloying, surface engineering, and environmental control were discussed. In addition, the applications of experimental simulation and numerical simulation in SCC research were summarized, and future research directions were prospected, such as the application of multiscale simulation and intelligent technologies. By integrating mechanistic research, technological innovation, and engineering practice, the theoretical support for constructing a full-chain protection system for SCC are provided, which can hold significant guiding value for the safe design and life assessment of metal materials.