Abstract: In the practice of carbon dioxide capture, utilization and storage, the storage of CO₂ in salt water layer has gradually become an effective way to deal with global warming, achieving the goal of net zero in 2050 and reducing CO₂ emissions due to its multiple advantages such as wide distribution area and large storage potential. TOUGHREACT/ECO₂N module in the Petrasim software was adopted to improve the storage efficiency of CO₂ in brine reservoirs. Based on the existing data of relevant geological storage projects in China and other countries, the numerical simulation method was used to evaluate the CO₂ dissolution quality and gaseous CO₂ saturation. The influence mechanism of five geological parameters of formation brine salinity, composition of formation brine, formation pressure, formation temperature and permeability on CO₂ sequestration was revealed, and the effect of CO₂ sequestration was quantitatively evaluated. The results show that: ① the geological parameters control the solubility, fluidity and mass transfer of formation fluids by changing the density and viscosity of CO₂, formation brine, CO₂ solubility and the chemical reaction of CO₂-brine and rock. ② The solubility of CO₂ and the density of formation brine decrease and increase with the increase of salinity respectively, with the former being mostly affected. The salinity has an inhibitory effect on the dissolution of CO₂. Therefore, the brine layer with low salinity is more conducive to increasing the storage capacity of CO₂ and improving the storage safety. ③ Among the four salt solution components obtained according to the Sulin classification method, the CO₂ dissolution quality corresponding to CaCl₂ water type is slightly lower than that of the other three water types. Overall, different salt solution components have little influence on the effect of CO₂ storage. ④ Under the combined effect of CO₂ solubility and gas-liquid two-phase viscosity ratio, the dissolved mass of CO₂ decreases with the increase of pressure and temperature, while the gaseous CO₂ saturation changes inversely. Permeability plays a direct role in controlling the gas mobility and migration distance. Therefore, with the lower formation pressure and temperature, the brine layer with higher permeability is more conducive to CO₂ storage.