Abstract: According to their genetic environments,CO 2 gas reservoirs may fall into five structural genetic types,and each type may be further divided into several subtypes according to the concrete formation conditions.The global CO 2 of inorganic origin is just distributed in the structural belts of the five genetic types.The CO 2 gas generation,migration and accumulation and reservoir trapping,capping and preservation are strictly controlled by the gas source fault system.As a case study,some gas reservoirs in eastern China are analyzed.