In　order　to　optimize　the　structure　of　multi-gap　gas　switch　used　in　fast　linear　transformer　driver(FLTD)　module,　the　electric　field　distribution　of　gas　switches　with　different　structured　electrodes　before　and　after　trigger　were　simulated.　The　effect　of　pressure　balance　measures　on　the　electric　field　distribution　of　the　gaps　in　the　gas　switch　before　trigger　was　studied　by　applying　the　new　circuit　model　of　the　gas　switch.　Moreover,　the　relationship　between　the　stray　capacitances　of　the　middle　electrodes　and　the　electric　field　distribution　in　the　gas　switch　after　trigger　was　studied.　The　results　show　that　the　ring　electrode　of　circular　section　is　conducive　to　the　formation　of　a　stable　multi-channel　discharge,　and　it　can　reduce　the　switch　inductance　and　jitter;　the　DC　voltage　characteristics　of　the　switch　can　be　effectively　improved　by　using　the　resistor　of　the　same　resistance　in　parallel　between　the　gaps.　At　the　trigger　moment,　the　voltage　distribution　of　each　gap　is　mainly　related　to　the　trigger　voltage　rise　time,　the　resistance　and　stray　capacitance,　and　the　shorter　the　trigger　voltage　rise　time　is,　the　more　obvious　the　effect　of　the　stray　capacitance　on　the　gap　voltage　distribution　is.