On-line　monitoring　of　high-voltage　electrical　equipment　(HV-EE)　aiming　to　detect　faults　effectively　has　become　crucial　to　avoid　serious　accidents.　Moreover,　highly　reliable　power　supplies　are　the　key　component　for　the　wireless　sensors　equipped　in　such　on-line　monitoring　systems.　Therefore,　in　this　paper,　the　wireless　power　supply　via　coupled　magnetic　resonance　(MR-WPS)　is　proposed　for　powering　the　wireless　sensor　and　the　associated　wireless　sensor　solution　is　also　proposed.　The　key　specifications　of　the　MR-WPS　working　in　switchgear　cabinet　with　a　harsh　operation　environment　are　analyzed　and　determined.　Design　of　these　key　parameters　of　the　coupled　magnetic　resonant　unit　(CMRU)　in　MR-WPS　is　provided　as　well　as　the　method　of　optimizing　the　resonant　windings　is　given.　Finally,　a　prototype　is　built　and　tested.　The　experimental　results　are　presented　in　order　to　show　that　sufficient　and　reliable　power　is　able　to　be　delivered　to　the　wireless　sensor　through　the　designed　MR-WPS,　and　therefore　the　theoretical　analysis　and　design　is　verified.