Design of electro-optically cavity-dumped Z-fold RF waveguide CO2 laser with common electrode is presented The structures of Z-fold and cavity dump are used for the transmitter laser to improve laser output power greatly at the condition of limited size. The construction of single channel is used for the local laser. The two channels are excited by the same RF source This kind of structure is helpful for improving the heterodyne frequency stabilization. In addition, the control method for the laser waveform of cavity dumps is analyzed in theory.