Aircraft　fuel　tank　fuel　explosion　is　a　threat　to　aviation　safety　is　one　of　the　main　factors.　The　Federal　Aviation　Administration　(FAA)　recently　to　the　airworthiness　regulations　was　revised,　the　provisions　of　the　aircraft　fuel　tank　in　the　upper　space　of　oxygen　content,　in　order　to　ensure　the　safety　of　flight.　This　paper　analyses　the　aircraft　fuel　tank　mixed　gas　combustion　causes　general　fuel　inerting　system　are　introduced.　And　for　the　lack　of　real-time　detection　of　oxygen　shortcomings,　introduces　a　kind　of　non　contact　of　the　mixed　gas　detection　technology.　Through　simulation　and　preliminary　exploration　of　the　feasibility　of　the　technique.