Transfer　efficiency　of　a　wireless　power　transfer　(WPT)　system　is　tightly　related　to　the　load,　which　varies　greatly　in　a　wide　range　during　the　charging　process.　Generally　speaking,　dual-sided　control　strategies　are　commonly　applied　to　overcome　the　load　variation　and　improve　system　efficiency.　However,　the　system　may　suffer　from　hard　switching,　high　control　complexity,　and　auxiliary　dc/dc　converters.　In　this　article,　a　dual-sided　control　strategy　based　on　mode　switching　is　proposed　to　approach　an　optimal　load　impedance,　zero-voltage　switching　of　all　mosfets　in　WPT　system,　and　a　required　output.　In　this　control　strategy,　the　output　voltage　of　the　inverter　is　adjusted　in　a　wide　range　by　switching　the　operation　mode　of　the　inverter　to　approach　the　optimal　load　impedance.　The　output　current/voltage　is　regulated　by　the　active　rectifier　control.　Besides,　a　novel　phase-locked　method　is　proposed　for　the　semi-bridgeless　active　rectifier　control,　which　is　simpler　compared　with　the　traditional　phase-locked　method.　Finally,　a　500-W　prototype　is　built　to　verify　the　theoretical　analysis,　and　the　peak　system　efficiency　of　93.9%　is　gained　with　k　=　0.23.