Abstract: Generating low-temperature plasma with high density requires fast pulses with high repetitive frequency, nanosecond rise time and nanosecond pulse width, which is very difficult for the widely used MOSFET and IGBT. Studies show that the bipolar junction transistors avalanche breakdown process has the characteristics of fast conduction, fast recovery and high stability, which is suitable for the self-breakdown switches in compact solid-state Marx generators. In this paper, it is found that the avalanche breakdown voltage can be adjusted by changing the resistance between BJTs gate and emitter. The experiments of avalanche breakdown and recovery show that BJT will turn off when the breakdown current attenuates below the maintain current, so the BJT avalanche breakdowns conduction time can be controlled by adjusting the parameters to change the attenuation of the discharging current in the circuit. Applying these conclusions to the actual circuit, fast pulses, with rise time of 5 ns, pulse width of 10 ns and amplitude of 2 kV and frequency of 100 kHz, are obtained.