Abstract: A crucial issue for the popularization of high viscous polymer devolatilization process is to develop high efficiency mass transfer apparatus with improved surface renewal rate. For the limitations of conventional apparatuses，a vertical rotating packed bed for high viscous polymer devolatilization process is proposed. The devolatilization mechanism of the proposed apparatus is illustrated by analogizing with the structure of screw extruder. Results show that the rotating packed bed has a higher devolatilization efficiency and a lower energy consumption as compared with conventional devices. Using the proposed vertical rotating packed bed，the acrylonitrile monomer removal efficiency from polyacrylonitrile can be achieved to over 99% upon twice devolatilized. As the desorbed volatiles can depart as soon from the packed bed and then be transfered by vacuum bump，this proposed technology will efficiently prevent the secondary dissolution of the volatiles.