Abstract: Self-triggered gas switch is an important option in pulsed power equipment with high breakdown stability requirements and inconvenient external trigger. The self-triggered switch based on UV-illumination technology has been successfully applied to the pulsed power equipment. In this paper, based on the breakdown process in the UV illuminated switch, main factors affecting the breakdown characteristics under different time scales and self-triggered methods are analyzed. The breakdown characteristics of the switch under different voltage rise-time are tested by experiments, including tens of nanoseconds, hundreds of nanoseconds, several microseconds and tens of microseconds. The experimental results show that the self-triggered switch has a lower breakdown voltage jitter, which can be less than 1.5%. And the breakdown time jitter of the switch can be limited below 1% of the rise-time. However, due to low trigger energy of self-triggered switch, it is difficult to obtain a lower jitter below several nanoseconds when the voltage rise-time is above several microseconds. A lower time jitter can be achieved by reducing the inductance of the energy storage module before the switch and reducing the rise-time charging on the switch.