In　recent　years,　Micro-light-emitting　diode　(Micro-LED)　has　attracted　much　attention　in　the　display　field,　because　it　provides　the　possibility　of　high　pixel　density,　etc.　The　implementation　of　high　pixel　density　is　accompanied　by　the　reduction　of　size,　during　which　the　performance　degradation　caused　by　sidewall　defects　gradually　increases.　At　the　same　time,　the　increase　in　power　density　and　difficulty　in　heat　dissipation　caused　by　high　pixel　density　can　also　lead　to　poor　thermal　management,　resulting　in　an　increase　in　junction　temperature,　thus　affecting　the　display　effect.　In　this　paper,　we　prepared　seven　different　sizes　of　Micro-LED　and　studied　the　influence　of　size　and　temperature　effects　on　the　optoelectronic　properties.　Smaller-sized　Micro-LED　could　withstand　higher　current　densities　because　it　was　not　affected　by　the　current　crowding　effect.　However,　it　tends　to　have　a　larger　series　resistance　(RS)　and　a　lower　external　quantum　efficiency　(EQE)　due　to　sidewall　defects　created　during　etching.　The　luminance　of　the　100　μm　and　7　μm　Micro-LED　was　340000　cd/m2　(at　83　A/cm2)　and　32000　cd/m2　(at　773　A/cm2),　respectively.　The　peak　EQE　of　100　μm　Micro-LED　was　16.87　%.　On　this　basis,　the　temperature-dependence　of　the　optoelectronic　properties　of　10　μm　and　50　μm　Micro-LED　were　studied.　The　larger　the　size　of　Micro-LED,　the　better　the　operational　stability　it　exhibited.　From　the　room　temperature　(RT)　rose　to　100　℃,　the　EQE　of　the　10　μm　and　50　μm　Micro-LED　decreased　by　16　%　and　13.1　%,　respectively.　These　experimental　results　provide　important　data　for　the　design　and　preparation　of　Micro-LED　of　different　sizes　and　for　exploring　the　operational　stability　at　high　temperatures.　©　2024