The CO2 storage of the deep saline aquifer is the most perspective CO2 geological storage way. This manuscript arranged papers which are related to researches of the CO2 geological storage, classifying geological conditions which is applied in the site selection evaluation of the saline aquifer CO2 storage, summarizing quantitative methods of the saline aquifer CO2 storage, and discussing main aspects of the uncertainty for the current CO2 geological storage. Current geological conditions for the site selection of the CO2 storage can be classified into two categories according to their different functions in the evaluation: the first category is the general condition for the feasibility evaluation and the second category is characteristics of the suitability and security of the storage which can be used to select the high- quality target area. Suitability features are more accurate features of reservoirs compared with the feasibility evaluation and the security evaluation focus on the suitability of cap rocks, the security of earthquakes, hydrogeological conditions, geological conditions of ground sites, the spatial distribution of reservoirs and cap rocks and structural features. The area method can be the prior consideration of the calculation of the storage volume in the large size area because of low requirements of materials. The volume method and the capacity coefficient method should be prior selection in the storage potential evaluation of high- quality target areas because of higher accuracy and the consideration of more storage mechanisms respectively. The uncertainty of the current geological evaluation of the saline aquifer storage lies in the following five aspects, which are respectively different impacts of geological factors in different aspects of evaluations, the uncertainty of the influence on the reservoir physical property produced by the CO2- water- rock reactions, special phenomena of the study, the insufficient understanding on the mechanism of various numerical simulations, and the uncertainty of parameters in the evaluation of storage potentials.