To meet the requirements of multi-channel precise synchronous trigger switch, photo conductive semiconductor switch (PCSS) is combined with V/N gas switch, which takes advantage of the photoelectric isolation, low trigger threshold, low delay time jitter and photoelectric isolation of PCSS, as well as the advantages of high operating voltage and strong load capacity of V/N gas switch. The core of the combination of the two switches is that the structural parameters of the V/N gas switch match the parameters of the PCSS trigger loop. The structural capacitance, trigger loop oscillation parameters and switching electric field distribution of the V/N gas switch are analyzed and calculated. The relationship between the structural capacitance of the V/N gas switch and the oscillation loop composed of PCSS and series inductors is studied. The self-breakdown voltage curve, on-delay time and delay time jitter of the switch under different under voltage ratios are obtained. The performance of the V/N gas switch for PCSS triggering is preliminarily verified.