Abstract Rotating packed beds (RPBs) are promising to be employed for CO2 capture from the flue gas due to their high mass transfer efficiency. Therefore, good predictions of the mass transfer characteristics for RPBs are crucial for their design. In this paper, a method based on CFD simulation is proposed to investigate the liquid film flows and mass transfer characteristics within RPBs. Local mass transfer coefficients along the radial direction of an RPB have been obtained. The results obtained show that high surface roughness and high rotational speed enhance the CO2 absorption into the liquid film, thus generating a high mass transfer coefficient, and the larger the RPB radial position, the higher the mass transfer coefficient.