Using double film theory, the mass transfer in the absorption process in ammonia-based CO2 capture under a static magnetic field was investigated in a bubbling reactor. The effect of the gas flow rate, CO2 inlet concentration, ammonia concentration, and reaction temperature on the interfacial area and mass transfer coefficients were investigated. Under a static magnetic field, the volumetric mass transfer coefficient of CO2 absorption for an ammonia concentration of 10 wt% reached 18.7x10(5) mol/(m(3) s Pa), which was 15.3% higher than that achieved without the magnetic field. By introducing the magnetic field, the estimated interfacial area per unit volume increased from 177.44 to 199.2m(2)/m(3) and the CO2 absorption process was promoted. In addition, the overall volumetric mass transfer coefficient and estimated interfacial area per unit volume were improved.