Huge amount of greenhouse gas emission of carbon dioxide leads to global warming, which poses challenging problems for both the survival of human beings and the social economic development. In an appropriately confined place, there may have a saline aquifer of huge storage volume, which is not very useful in itself, but the volume can be used to store CO₂. Based on the mechanism of storing CO₂ in a saline aquifer, the influencing factors of a reservoir and the fluid in storing CO₂ in a saline aquifer are studied in this paper by adopting the Eclipse software. The simulation results show that the permeability, the ratio of the vertical and the horizontal permeability and the rhythm are the main influencing factors of the CO₂ storage volume in the saline aquifer. The salinity and the temperature are the main influencing factors of CO₂ dissolved volume in the saline aquifer. We can draw some guidance for the CO₂ storage in the field.