The present disclosure provides a method for regenerating aqueous ammonia after capturing carbon dioxide with aqueous ammonia. The method includes following steps: providing an aqueous ammonia regenerating system, performing a first flashing step, performing a first compressing step, performing a stripping step, performing a second flashing step, performing a second compressing step. The aqueous ammonia regenerating system includes a heat exchanger, a stripper, a second pump, a first flash drum, a first compressor, a second flash drum and a second compressor. Accordingly, the present disclosure can effectively reduce the energy penalty of capturing carbon dioxide by disposing the first flash drum between the heat exchanger and the stripper, and replacing the conventional reboiler with the second flash drum, so as to achieve the purpose of energy saving. |