The generator includes pulse forming circuit, pulse amplifier cirucit and high-frequency and high-voltage sawtooth wave generating circuit. The output signal of the pulse amplifier circuit is fed to the high-frequency and high-voltage sawtooth wave generating circuit to control the on-off of its tetrode, and the high-voltage power source charges and discharges through its own inductor and capacitor. By means of the high-frequency and high-power electronic tube as high-voltage control switch and the direct charge and discharge to inductor and capacitive load, the present invention produces high-frequency and high voltage sawtooth wave directly in capacitive load with perfect wave form and high peak-to-peak value.