Low-speed　permanent　magnet　synchronous　generator　(PMSG)　has　the　characteristics　of　high　torque　and　low　voltage.　This　study　presents　an　optimized　design　about　an　outside　rotor　10　kW　low　speed　PMSG　which　is　in　the　vertical　vane　wheel　hydro-generator　unit.　Maxwell　software　is　used　to　establish　the　finite　element　model　of　the　low-speed　PMSG,　and　the　simulation　analysis　including　three-phase　flux　waveforms,　induced　voltage　waveforms,　voltage　waveforms,　current　waveforms,　flux　density　distribution　and　torque　characteristic　curve　is　carried　out　under　the　no-load　and　rated　load.　Simulation　results　show　that　the　low-speed　PMSG,　which　has　the　skew　stator　core　and　fractional　slot　concentrated　winding,　has　a　series　of　advantages　of　low　cogging　torque,　high　efficiency,　small　output　voltage　harmonics　and　low　waveform　sine　distortion　rate,　fully　meeting　the　design　requirements.　©　2018,　Springer　International　Publishing　AG.