This　paper　analyzed　the　coupled　inductor　model　and　the　transformer　T　model　of　the　magnetic　coupling　system　in　the　wireless　power　transfer　(WPT)　based　on　the　circuit　theory.　The　principle　of　the　different　equivalent　ratio　by　the　same　magnetic　coupling　system　was　got.　And　a　new　idea　is　proposed　in　which　any　constant　WPT　voltage　gain　can　be　got　by　compensation　network　design　for　a　given　magnetic　coupling　system.　According　to　the　multi-solutions　of　the　transformer　T　model　(including　the　equivalent　leakage　inductance　in　primary　winding　Lpk,　the　equivalent　leakage　inductance　in　secondary　winding　Lsk,　the　equivalent　exaction　inductance　Lm　and　the　equivalent　ration　n),　the　relationship　between　the　Lpk,　Lsk,　Lm　and　n　were　established.　By　designing　the　compensation　parameters　for　the　resonant　compensation　of　the　corresponding　equivalent　leakage　inductance　at　different　equivalent　ratio　n,　the　WPT　system　could　obtain　variable　voltage　gain.　The　design　concept　is　clear　and　the　model　is　simple　which　can　help　to　effectively　broaden　the　range　of　output　voltage　gain.　With　the　same　input,　output　and　frequency　specification,　the　winding　turns　and　the　size　of　the　magnetic　coupling　system　can　be　reduced　which　is　good　for　the　footprint　reduction　of　the　magnetic　coupling　system.　Finally,　the　experiment　results　verified　the　theory　analysis　to　be　correct　and　useful.　©　2017　Chin.　Soc.　for　Elec.　Eng.