A method for designing a carbon dioxide capture process, according to the present invention, comprises: a target setting step of setting a target purity and a target capture ratio; a calculation step of calculating the number of stages, which is the number of separation membrane modules forming a permeate side flow chain, and the number of treatments, which is the number of separation membrane modules forming a pass side flow chain, by using the target purity, the target capture ratio, and separation performance data of the separation membrane module, which treats injected gas so as to discharge the same as a permeate side flow and a pass side flow; and an arrangement step of arranging the separation membrane modules of which the number is the same as the calculated number of stages along the permeate side flow chain, and arranging the separation membrane modules of which the number is the same as the calculated number of treatments along the pass side flow chain such that the pass side flow chain receives the injected gas so as to discharge a discard flow, and thus the carbon dioxide capture process, which includes the permeate side flow chain receiving the injected gas so as to discharge a final carbon dioxide discharge flow and the pass side flow chain receiving the injected gas so as to discharge the discard flow, is formed.