In order to provide the ideal light source for difference frequency THz laser device, the methods of pulsed laser output synchronization have been studied for two 10 μm radio-frequency (RF) excited pulsed waveguide CO2 laser with grating. One method was to control the pulse triggering delay, and the other was to adjust the voltage on the piezoceramics (PZT). The pulsed laser output synchronization could be realized by the two methods. It is helpful to obtain high efficiency THz generation. In the experiment, because of the ambient temperture, vibration and other external conditions, it is found the output pulsed laser synchronization maintains a relatively short time, but the pulsed laser can be re-synchronized by manually controling the pulse trigger delay or adjusting the PZT voltage.