The invention provides a degassing method used during production of ethylene propylene rubber. The degassing method comprises the following steps: filtering polymer liquid discharged from a polymerizing kettle (D-1) by a filter so as to remove macromolecular polymers; heating the polymer liquid by a heater (E-2) so as to provide a part of heat for gas; degassing the polymer liquid heated by the heater (E-2) in a degassing tower (T-1) so as to extract unreacted monomers. By the degassing method, the mass transfer and heat transfer efficiency of a material is enhanced and blockage of the heater is avoided.