For　power　supply　of　wireless　temperature　measuring　device　of　high-voltage　equipment,　a　new　on-line　temperature　monitoring　system　powered　by　low-voltage　LED　light　was　designed.　A　solar　cell　was　used　to　convert　LED　light　energy　to　electric　energy　for　reliable　operation　of　the　high-voltage　wireless　temperature　measuring　device.　A　two-stage　PWM　dimming　constant　current　LED　driver　was　designed　to　provide　constant　current　for　LED　and　ensure　high　power　factor　at　input　terminal.　Temperature　signals　are　collected　with　thermistor　PT1000　and　transmitted　with　ANT　wireless　communication　module　in　the　wireless　temperature　measuring　device,　which　has　the　advantages　of　high　precision　and　low　power.　Experiments　show　that　the　average　current　consumption　of　the　wireless　temperature　measuring　device　is　7.24　mA　under　3.3　V　voltage,　and　the　output　current　of　the　driver　is　584　mA　with　PWM＇s　full　duty　cycle.　The　working　condition　with　70%　of　PWM＇s　duty　cycle　is　the　best　condition,　in　which　reliable　operation　of　high-voltage　circuit　and　power　saving　are　balanced.　©　2017,　Xi＇an　High　Voltage　Apparatus　Research　Institute　Co.,　Ltd.　All　right　reserved.