Abstract: The generation and coupling out of high power wideband microwave based on the switched quarter-wavelength coaxial transmission line oscillator has been addressed. The switched oscillator works at 200 MHz, and is comprised of quarter-wavelength long coaxial transmission lines with a ring-shaped multichannel gaseous spark gap switch at one end. The coupler consists of blocking capacitor and distributed inductance. The generation and coupling out of wideband micorwave in the oscillator was simulated by commercial software. The switching characteristics were also studied. The results of simulation and experiment verify that directly-fed, high impedance and tooth socket structure can improve the stability of the multichannel switch. The wideband microwave generation system has been set up and charged by a high power Marx pulse source with output voltage of 500 kV. The center frequency of radiation is 195 MHz. The radiated peak electric field at a distance of 1 m is 150 kV and the full width at half maximum of frequency spectrum is about 30%.