Climate change incurred by the increasing amount of CO2 released into the atmosphere has become a global priority, and triggers the development of carbon capture, utilization, and storage. Low energy requirement and cost by employing moisture swing process make quaternary ammonium-based materials applicable for CO2 capture. The moisture-sensitive sorbents suffer decreased CO2 affinity and cyclic capacities with moderate or high humidity, while water vapor ubiquitously exists in flue gas or ambient air. The effect of applying electric field on CO2 adsorption, especially the water-involved proton transfer step, by quaternary ammonium-based sorbents in the existence of water, is analyzed. The discrepancy in the hydrophilicity between reactant and product species is enhanced by the electric field, which indicates more favorable chemisorption. Thermodynamics of CO2 adsorption coupling interfacial water evaporation under the electric field are depicted with changes of enthalpy and free energy calculated. Therefore, the rationality of electric field enhanced CO2 capture of quaternary ammonium-based sorbents in moist circumstance is theoretically validated, providing the methodology of optimizing moisture swing adsorption from process intensification apart from material design.