Thermal　properties　and　spectroscopic　properties　of　the　glass　micro-sphere　were　presented　in　this　paper.　The　Er3+　emission　spectra　of　a　kind　of　Erbium-doped　glass　microsphere　were　measured　and　discussed　under　532nm　excitation　in　a　series　of　temperatures.　The　change　in　the　temperature　of　the　microsphere　leads　to　a　change　in　both　the　size　and　the　index　of　refraction　of　the　sphere,　which　results　in　the　resonance　shift　of　the　peaks　of　whispering　gallery　modes　in　emission　spectra.　The　temperature　of　the　environment　surrounding　the　sphere　can　be　determined　by　monitoring　the　shift,　which　allows　us　to　calibrate　the　sensing　function　of　the　shift　proportional　to　temperature.　Based　on　the　thermal　effects,　we　propose　a　novel　optical　temperature　sensor　using　micrometer-sized　sphere.