Aiming　at　the　power　loss　caused　by　photovoltaic　(PV)　mismatch　problem,　a　distributed　maximum　power　point　tracking　(DMPPT)　Flyback　type　PV　grid-connected　inverter　and　the　sinusoidal　pulse　width　modulation(SPWM)　unified　control　strategy　with　DMPPT　are　proposed.　Meanwhile,　the　circuit　topology,　operation　modes　and　steady　state　relations　are　deeply　investigated.　The　inverter　is　composed　of　n　Buck　choppers　with　their　outputs　connected　in　series　and　a　Flyback　type　grid-connected　inverter,　it　belongs　to　quasi-single-stage　power　conversion.　The　control　strategy　achieves　the　DMPPT　of　all　PV　cells　and　the　control　of　grid-connected　current　simultaneously.　Designed　and　implemented　500W　27-39VDC/220V50HzAC　prototype　has　excellent　performances　such　as　high　PV　cell　utilization　efficiency,　low　cost,　high　conversion　efficiency,　high　reliability,　high　quality　of　output　waveforms,　etc.