Abstract: The trigger breakdown characteristic experiment of two-gap switches with hollow and non-hollow trigger electrodes was done. The breakdown jitter and channel number of the two gaps were compared, and the interaction mechanism between the two gaps in cascade was analyzed. The experiment result shows that the change rule of breakdown jitter and channel number of trigger gap in two switches is basically same. The breakdown jitter of self-breakdown gap in non-hollow switch decreases with the increase of working coefficient, and the minimum jitter is about 3 ns. The breakdown jitter of self-breakdown gap in hollow switch is always about 1 ns. Multiple discharge channels are generated difficultly in self-breakdown gap of non-hollow switch, and the channel number in self-breakdown gap of hollow switch is obviously larger than that of other gaps. The self-breakdown gap can be pre-ionized to generate initial electrons by ultraviolet from the breakdown of trigger gap through the hollow hole, which is the main reason for the low breakdown jitter and larger channel number of self-breakdown gap.