In　this　paper,　an　autonomous　wireless　power　transfer　(WPT)　system　with　constant　voltage　output　in　a　wide　load　range　is　presented.　Here,　combining　self-oscillating　control　and　phase-shift　control,　a　new　implementation　of　the　autonomous　WPT　system　is　proposed.　The　proposed　autonomous　WPT　system　operates　using　a　self-oscillating　control　method　in　the　strong　coupling　region,　which　can　automatically　maintain　the　constant　output　voltage.　In　the　weak　coupling　region,　a　phase-shift　control　method　with　a　fixed　frequency　and　a　variable　duty　cycle　is　implemented,　and　a　control　strategy　based　on　output　voltage　estimation　is　proposed　to　obtain　the　constant　output　voltage.　In　addition,　according　to　the　operating　frequency　characteristic　of　the　proposed　autonomous　WPT　system,　a　corresponding　coupling　region　judgment　method　is　presented　to　guarantee　the　realization　of　switching　between　the　two　control　methods.　An　experimental　prototype　with　a　24　V　output　voltage　is　constructed　to　validate　the　practicability　of　the　proposed　method.　The　experimental　results　show　the　proposed　autonomous　WPT　system　can　obtain　constant　output　voltage　in　a　wide　load　range.