As the global warming has been accelerated due to the indiscreet use of fossil fuels, various efforts are conducted to decrease the CO2 concentration in atmosphere. The electrochemical CO2 reduction has been recognized as the eco-friendly technology that CO2 can be converted to useful products. However, for the commercialization of this technology, it is necessary to acquire the minimum 200 mA/cm2 of current density with high product selectivity. Unlike the conventional H-type cell system, the gas-phase CO2 electrolysis system facilitates much faster reactant supply into electrode which can overcome the CO2 masstransport limitation. In this review, we introduce the gas-phase CO2 electrolysis technology, according to the electrolyzer configuration. In the case of gas-phase CO2 electrolyzer containing catholyte layer has an advantage of facile formation of triple-phase boundary for the reaction, resulting in excellent operating stability. On the other hand, the membrane electrode assembly-based CO2 electrolyzer shows the lower ohmic resistance than other configurations that can reduce the operating cell voltage. These investigations can accelerate the commercialization of CO2 electrolysis system.