Abstract: A coaxial field distortion gas spark switch was designed and experiments were carried out to study the effect of trigger pulse peak on discharge channel number of the switch gaps in N2 in two cases. In the first case, only the trigger pulse was applied to the switch, while in the second, the inner and outer electrodes were connected to two capacitors with positive and negative charge respectively. The numbers of discharge channels in the two cases were compared. In the first case, discharge channels carry lower current. The average number of channels in the switch inner gap increases obviously with increasing trigger pulse peak in the first case, while the average number of channels in the switch inner gap increases and the average number of channels in the switch outer gap decreases in the second case. Under similar overvoltage multiples, the average number of channels in the second case is smaller.