The　content　of　acetylene　is　one　of　the　important　indicators　of　transformer　fault　diagnosis.　Due　to　the　differences　between　individual　transformers,　the　content　of　acetylene　gas　varies　greatly.　The　adoption　of　a　single　threshold　is　likely　to　lead　to　false　alarm　or　missing　report　of　the　diagnosis　results.　The　difference　of　gas　threshold　in　oil　has　been　paid　more　and　more　attention,　but　the　difference　characteristics　of　acetylene　gas　threshold　in　oil　and　its　influencing　factors　are　still　unclear.　This　paper　uses　10　kV　test　transformer　and　fault　chamber　to　build　a　simulation　test　platform　for　gas　production　and　diffusion　under　pin　plate　and　column　plate　faults.　The　acetylene　content　in　different　stages　of　fault　development　was　measured,　and　the　gas　distribution　model　was　statistically　analyzed.　On　this　basis,　based　on　the　P-R　curve,　the　attention　value　and　warning　value　of　acetylene　content　during　the　development　of　two　kinds　of　faults　are　calculated,　and　the　difference　of　threshold　values　of　different　oilpaper　materials　is　compared.　The　results　show　that　there　are　obvious　differences　in　acetylene　thresholds　under　different　oil　paper　materials　and　faults,　and　the　sensitivity　and　accuracy　of　fault　diagnosis　based　on　oil　chromatography　can　be　improved　by　using　the　calculated　differential　threshold.　　©　2023　IEEE.