An electrooptically Q-switched RF excited waveguide CO2 laser with two channels is demonstrated. The Q-switched pulse laser has been obtained from one of the channels with a grating. The peak power is 150 W and the pulse width is 180 ns. CW laser output has been obtained from the other channel, which can been tuned by a PZT. In addition, the tuning range of the laser heterodyne frequency is analyzed in theory and the largest tuning range is 150 MHz in experiment.