Under the background of global advocacy of energy transition and energy conservation and emission reduction, efficient storage and "green hydrogen" utilization has become an important trend in the future development of energy industry, and underground hydrogen storage in saline aquifers has also become a new large-scale energy storage technology with great potential. The development statues of hydrogen storage reservoir in saline aquifers was reviewd, the research and application progress of numerical simulation method applied in hydrogen-saline system were illustrated, and the technical difficulties were concluded in thermal-hydrodynamic-mechanical-chemical (THMC) coupling numerical simulation models and methods. The results show that underground hydrogen storage in saline aquifers has the advantages of safety, controllability, high efficiency and flexibility, and large storage capacity, and its mature application can achieve a win-win situation of economic, social and ecological benefits; numerical simulation method is an effective means to study underground hydrogen storage (UHS) while it's still in the initial developing stage. The optimization of numerical simulation and global algorithm is helpful to realize the design of saline reservoir engineering. Applying injection-production scheme designing, artificial intelligence technology can provide certain references for optimization.