The　development　of　new　high-performance　gas　sensors　has　become　particularly　urgent　with　the　growth　of　global　energy　demand　and　the　aggravation　of　environmental　problems.　Biomass　char　materials　are　obtained　from　biomass　raw　materials　through　pre-carbonization　and　activation　treatment,　which　have　unique　pore　structure,　large　specific　surface　area,　abundant　surface　active　functional　groups　and　active　sites,　and　have　great　potential　for　application　in　the　field　of　gas　sensing　and　detection.　In　this　paper,　biomass　is　classified　according　to　the　main　sources　of　biomass　char　(plant-based,　animal-based,　and　microbial-based)　as　well　as　four　common　preparation　methods　of　biomass　char　materials　(hydrothermal　carbonization,　activation,　templating,　and　microwave　pyrolysis).　The　paper　focuses　on　the　recent　research　progress　of　biomass　char　materials　in　semiconductor-based　gas　sensors　and　non-metallic　oxide　dominated　gas　sensors,　including　their　applications　as　gas-sensitive　materials　for　the　detection　of　various　types　of　gases.　Finally,　the　current　problems　that　need　to　be　solved　for　biochar-based　gas　sensors　are　analyzed,　and　ideas　for　research　and　development　are　proposed　to　broaden　the　practical　applications　of　such　sensors.　©　2025　Beijing　University　of　Aeronautics　and　Astronautics　(BUAA).　All　rights　reserved.