Thermal　runaway　in　lithium-ion　batteries　generates　toxic　and　flammable　gases　such　as　CO,　C2H2,　and　C2H4,　presenting　severe　safety　risks.　Early　detection　of　these　gases　is　essential　for　battery　safety　monitoring.　In　this　study,　the　gas　sensing　performances　of　pristine　and　Pt-doped　indium　selenide　(InSe)　monolayers　toward　CO,　C2H2,　and　C2H4　were　investigated　using　first-principles　density　functional　theory　(DFT).　The　adsorption　energies,　charge　transfer,　and　electronic　structure　changes　were　systematically　analyzed　to　evaluate　sensing　sensitivity.　Results　indicate　that　pristine　InSe　exhibits　weak　interaction　with　all　target　gases.　However,　Pt　doping　significantly　enhances　gas　adsorption　with　increased　adsorption　energies　and　substantial　charge　transfer.　The　Pt　dopant　also　modulates　the　electronic　structure　of　InSe,　which　is　favorable　for　sensing　signal　transduction.　These　findings　demonstrate　that　Pt-doped　InSe　monolayers　possess　excellent　selectivity　and　sensitivity　toward　critical　warning　gases　from　thermal　runaway,　offering　theoretical　guidance　for　the　design　of　high-performance　2D　material-based　gas　sensors.