The thermal relaxation rates of the vibrational levels (0001) and (1000) of CO2 molecules in a discharged positive .column have been measured by OGE. The dependences of the thermal relaxation rates on the incident intensity, discharge current, pressure and foreign gasea have also been investigated. The approximate values of T001 and T100 obtained are 0.6-1.5 ms and 0.2-0.8 ms respectively.