Aiming　at　the　problem　of　reducing　the　instantaneous　noise　of　vacuum　circuit　breaker　closing,　the　noise　reduction　system　for　rail　transit　vehicles　is　innovatively　designed　by　using　TRIZ　theory.　Through　function　analysis　and　cause-effect　chain　analysis,　this　paper　finds　the　root　cause　of　the　problem,　solves　the　problem　and　puts　forward　the　scheme　by　establishing　the　technical　contradiction,　physical　contradiction　and　su-field　model,　and　finally　puts　forward　the　design　of　the　noise　reduction　system,　so　as　to　provide　a　theoretical　basis　for　the　development　of　subsequent　products.