Since　the　magnetic　field　distribution　in　winding　window　of　thin　film　micro-inductor　with　closed　magnetic　core　has　obvious　2-D　characteristics,　the　accuracy　of　1-D　analytical　model　for　its　winding　AC　losses　is　poor.　The　magnetic　field　of　the　micro-inductor　is　analyzed　deeply　to　show　that　its　distribution　along　the　winding　edge　does　not　change　with　frequency.　According　to　the　analysis　result,　the　magnetic　field　strength　around　the　winding　edge　is　calculated　with　the　Ampere＇s　law.　And　the　2-D　magnetic　field　is　decomposed　into　an　x　component　and　y　component　in　rectangular　coordinates.　Then　based　on　the　superposition　and　uniqueness　law　of　magnetic　field,　a　2-D　analytical　winding　losses　model　of　thin　film　micro-inductor　is　proposed.　Finally,　the　finite　element　analysis　(FEA)　simulation　verified　the　loss　model　to　have　high　accuracy　under　wide　exciting　current　frequency　and　the　loss　model　can　be　used　easily.　©　2019　IEEE.