In　this　paper,　the　principle　of　the　methane　gas　enhanced　the　laser　absorption　by　the　WGM　of　high-Q　microsphere　was　studied.　A　taper　optical　fiber　was　used　as　a　coupler　to　couple　1653.72　nm　laser　into　a　microsphere　with　a　optical　fiber　handle　to　form　whispering　gallery　mode(WGM).　The　resonant　wavelength　of　the　microsphere　cavity　was　changed　to　1653.72　nm　by　injecting　heating　light　along　the　handle,　so　that　one　resonant　wavelength　of　the　microsphere　is　just　1653.72　nm.　The　1653.72　nm　laser　forms　WGM　continuously　to　surround　the　microsphere,　and　the　effective　optical　path　is　greatly　increased,　which　increases　the　interaction　distance　with　methane,　and　thus　the　sensitivity　of　methane　detection　is　improved.　The　results　show　that　the　microsphere　with　WGM　can　be　used　as　a　gas　sensor.　　©　Published　under　licence　by　IOP　Publishing　Ltd.