This　paper　presents　a　free　piston　expander-linear　generator　(FPE-LG)　for　small　scale　organic　Rankine　cycle　(ORC).　Based　on　FPE-LG　experiment　configuration,　performance　investigation　and　efficiency　analysis　on　FPE-LG　are　conducted.　Experiment　results　show　that　intake　pressure　and　external　load　resistance　have　great　influence　on　actual　stroke,　velocity　and　exhaust　temperature.　The　exhaust　pressure　is　hardly　relevant　to　intake　pressure　and　operation　frequency.　When　FPE-LG　operates　with　low　operation　frequency,　the　entropy　generation　decreases　with　intake　pressure,　whereas　it　increases　with　intake　pressure　when　the　operation　frequency　is　high.　The　indicated　work　increases　when　increasing　the　intake　pressure　and　external　load　resistance,　whereas　it　decreases　when　increasing　operation　frequency.　The　indicated　efficiency　decreases　with　the　intake　pressure　and　external　load　resistance,　and　the　maximum　indicated　efficiency　can　reach　up　to　81%.　The　voltage　and　power　output　increase　when　the　intake　pressure　and　external　load　resistance　increase,　and　the　maximum　voltage　and　power　output　can　reach　44.4　V　and　111.6　W,　respectively.　High　energy　conversion　efficiency　can　be　achieved　in　the　area　of　high　external　load　resistance　and　intake　pressure.　Generally,　the　higher　power　output　is,　the　higher　energy　conversion　efficiency　is.　The　maximum　energy　conversion　efficiency　of　73.4%　is　achieved.