The time-resolved diode laser spectroscopic method was applied to the characterization of pulsed CO 2 laser-excited SF 6. The transient signals of rotation-vibration lines of CO, which was added to the system as monitor gas, were observed and dynamic changes of vibrational, rotational and translational temperatures ( T V, T R and T T) of CO were obtained. The T R and T T of CO increased within 30 μs after the CO 2 laser shot, while the T V of CO increased gradually in the time range of 0–1 ms at 1 Torr of SF 6. The rise rate of T R was determined to be (1.0±0.1) × 10 5 s −1 Torr −1 from measurements in various pressures of SF 6, and the result was explained by V-T, R energy transfer in highly excited SF 6. The temperature determined from energy absorption measurements was compared with the T R of CO.