Er3+-doped　silica　microspheres　with　smooth　surface　are　fabricated　through　surface　tension　induced　by　heating　and　fusing　a　single　tapered　silica　fiber　between　two　discharge　electrodes.　The　tapered　fiber　is　dipped　with　quantitative　erbium　nitrate　solution.　Single　mode　laser　of　976　nm　is　coupled　into　microsphere　through　near-field　coupling　by　evanescent　wave　from　biconical　tapered　fiber,　exciting　high　power　density　whispering　gallery　modes　(WGM)　in　the　microsphere.　And　downconversion　emission　spectrum　of　C+L　band　of　optical　communication　is　obtained,　which　is　emitted　from　stimulated　Er3+　distributing　all　over　the　surface　of　microsphere.　Single-longitudinal-mode　and　multi-longitudinal-mode　lasers　are　also　measured　at　around　1555　nm　and　1600　nm.　The　diameters　of　the　microspheres　tested　in　our　experiment　are　between　70~150　μm,　and　the　concentration　of　the　erbium　nitrate　solution　is　about　10-5~10-4　mol/mL.　The　methods　of　microsphere　fabrication　and　rare　earth　doping　are　simple　and　practicable　for　fast　measurement　of　the　luminescence　of　rare　earth　doped　materials.