The 12-stage linear transformer driver (LTD) adopts the novel method of internal in situ triggering in sequence, and puts forward the technical requirements of low pre-fire probability, low trigger threshold voltage, low jitter and adjustable trigger delay time for the trigger brick gas switches. This paper introduces the structure and working principle of the trigger brick gas switch based on resistance voltage balance and corona assisted triggering technology. The test platform of gas switch characteristics is established, and after the process of conditioning, the breakdown characteristics of 12 gas switches are tested. Then, the switches are applied to the 12-stage LTD to carry out cascade triggering experiments, and the triggering characteristic parameters under different charging voltages and working coefficients are obtained. The experimental results show that, when the charging voltage of the switch is ±60-±80 kV and the working coefficient is 60%-80%, the jitter is lower than 2 ns, and there is no pre-fire in more than 500 shots. The trigger brick gas switches of the 12-stage LTD can be sequentially closed according to the ideal sequence, and the trigger sequence coefficient can be adjusted in the range of 0.83-1.17.