Whispering　gallery　mode　is　a　type　of　optical　mode　where　photons　move　in　a　quasi-two-dimensional　plane,　and　the　total　reflection　occurs　at　the　boundary　of　the　microcavity　without　reflecting　out　of　the　cavity.　This　mode　has　a　high　Q　value　and　small　mode　volume,　and　it　is　extremely　sensitive　to　changes　in　the　surrounding　environment.　A　broadband　fluorescence　can　be　transformed　into　narrow-spectrum　laser　output　by　using　the　whispering　gallery　mode.　In　this　paper,　polystyrene　microspheres　doped　with　the　dragon　green　fluorescent　dye　are　used　as　whispering　gallery　mode　optical　microcavity.　Through　the　phagocytosis　of　cells,　the　fluorescent　microspheres　reach　inside　cells　and　then　are　pumped　by　nanosecond　pulsed　laser　to　achieve　the　output　of　whispering　gallery　mode　laser　in　cells.　In　comparison　with　the　laser　output　in　the　pure-water　environment,　a　redshift　of　the　intracellular　fluorescent　microsphere　whispering　gallery　mode　resonance　emission　can　be　observed,　and　the　redshift　is　related　to　cell　type;　therefore,　it　can　be　used　for　unlabeled　identification　of　cell　type.　©　2020,　Chinese　Lasers　Press.　All　right　reserved.