In　the　mobile　phone　wireless　power　transfer　(WPT)　system　with　magnetic　core,　the　loss　caused　by　the　magnetic　core　and　winding　is　the　central　part　of　the　system　loss.　Among　them,　the　core　loss　is　mainly　related　to　magnetic　materials,　working　frequency,　magnetic　flux　density　and　other　factors　in　the　core;　The　winding　loss　is　mainly　related　to　the　current　flowing　through　the　winding　and　the　resistance　of　the　winding.　In　this　paper,　it　analyses　the　influence　of　the　working　frequency,　the　number　of　turns,　the　number　of　strands　of　Litz　wire　and　different　turn-width　of　the　winding　on　the　loss　of　the　system.　Finally,　according　to　the　analysis　results,　the　coils　within　the　allowable　range　of　working　frequency　and　current　of　transmitting　and　receiving　coils　are　made　to　verify　the　feasibility　of　the　optimization　scheme.　The　simulation　and　experimental　results　show　that　the　coil　loss　of　the　optimized　scheme　will　be　reduced　under　the　condition　that　the　current　and　phase　flowing　into　the　coils　are　equal.　©　2022　The　authors　and　IOS　Press.