For the requirements of low-jitter and long working-life triggered gas switches in actual conditions, a polycyclic type gas switch are designed, based on the analysis of the structures of two three-electrode gas switch, and the main electrodes and trigger electrodes of two switches are plate-disk and spherical-disk. The main electrode of polycycclic type gas switch is plate electrode and the trigger electrode is composed of three circles and four pillars. With the combination of two electrodes, we expect to reduce the breakdown time delay and jitter, while ensuring the working life of the switch as much as possible. The breakdown characteristics of trigger switches, include plate-polycyclic, plate-disk, and spherical-disk, are tested. The test results prove that, under 5.0kV~7.5kV loading voltage, the plate-polycyclic type switches are more stable. The breakdown time delay of plate-polycyclic type switches are 81.0ns~84.5ns, and the breakdown time jitter are 0.8ns~1.1ns, that is almost identical to that of spherical-disk type switch, and shows better performance than plate-disk type switch. The breakdown time delay of plate-disk type switch are scattered among 82.4ns~85.2ns; and breakdown time jitter is two times of the others; In terms of working life, the main electrode of plate-polycyclic switch is flat type, and its effective use area is significantly larger than that of spherical-disk type switch, so its working life are improved compared to spherical-disk type switch.