A carbon dioxide (CO 2) chemical absorption system comprising: a CO 2 absorption column for separating CO 2 from combustion exhaust gas by absorbing the CO 2 in the combustion exhaust gas with a CO 2 absorbing liquid composed of an aqueous alkanolamine solution; a regeneration column for regenerating the CO 2 absorbing liquid by desorbing CO 2 gas from the CO 2 absorbing liquid that has absorbed CO 2, wherein the regeneration column comprises a packed bed and a water washing part over the packed bed, wherein the entire CO 2 absorbing liquid that has absorbed CO 2 is fed to a top portion of the packed bed; a condenser for condensing water vapor entrained.in the desorbed CO 2 gas discharged from the top of the regeneration column, thereby obtaining reflux water; a pipe for returning all or part of the reflux water obtained by the condenser to the top of the regeneration column, and for dispersing the reflux water to the water washing part in the regeneration column, wherein the reflux water is fed to the top portion of the water washing part; a collection plate for collecting the reflux water dispersed to the water washing part in the regeneration column and for preventing the dispersed reflux water from flowing into the packed bed, wherein the collection plate is located between the water washing part and the packed bed, and the desorbed CO 2 and entrained water vapour pass through the collection plate and are fed to the water washing part; a pipe for sending the regenerated CO 2 absorbing liquid from the bottom of the regeneration column to the top of a packed bed in the absorption column, the pipe comprising a heat exchanger for heating the CO 2 absorbing liquid that has absorbed CO 2 which is sent from the absorption column to the regeneration column and cooling the regenerated CO 2 absorbing liquid which is sent along the pipe, and the pipe further comprising a cooler between the heat exchanger and the absorption column; and a pipe for joining the reflux water collected by the collection plate into the pipe for sending the regenerated CO 2 absorbing liquid at a position between the heat exchanger and the cooler. a CO 2 absorption column for separating CO 2 from combustion exhaust gas by absorbing the CO 2 in the combustion exhaust gas with a CO 2 absorbing liquid composed of an aqueous alkanolamine solution; a regeneration column for regenerating the CO 2 absorbing liquid by desorbing CO 2 gas from the CO 2 absorbing liquid that has absorbed CO 2, wherein the regeneration column comprises a packed bed and a water washing part over the packed bed, wherein the entire CO 2 absorbing liquid that has absorbed CO 2 is fed to a top portion of the packed bed; a condenser for condensing water vapor entrained.in the desorbed CO 2 gas discharged from the top of the regeneration column, thereby obtaining reflux water; a pipe for returning all or part of the reflux water obtained by the condenser to the top of the regeneration column, and for dispersing the reflux water to the water washing part in the regeneration column, wherein the reflux water is fed to the top portion of the water washing part; a collection plate for collecting the reflux water dispersed to the water washing part in the regeneration column and for preventing the dispersed reflux water from flowing into the packed bed, wherein the collection plate is located between the water washing part and the packed bed, and the desorbed CO 2 and entrained water vapour pass through the collection plate and are fed to the water washing part; a pipe for sending the regenerated CO 2 absorbing liquid from the bottom of the regeneration column to the top of a packed bed in the absorption column, the pipe comprising a heat exchanger for heating the CO 2 absorbing liquid that has absorbed CO 2 which is sent from the absorption column to the regeneration column and cooling the regenerated CO 2 absorbing liquid which is sent along the pipe, and the pipe further comprising a cooler between the heat exchanger and the absorption column; and a pipe for joining the reflux water collected by the collection plate into the pipe for sending the regenerated CO 2 absorbing liquid at a position between the heat exchanger and the cooler.