In　this　paper,　a　new　free　piston　expander-linear　generator　(FPE-LG)　prototype　for　small-scale　organic　Rankine　cycle　(ORC)　waste　heat　recovery　system　has　been　developed.　Firstly,　the　in-cylinder　pressure,　motion　characteristics　and　output　performance　of　the　FPE-LG　with　different　valve　timings　are　investigated.　Then,　the　effect　of　external　load　resistance　on　motion　characteristics　and　output　performance　with　cam　plate　A　is　analyzed.　Finally,　the　effect　of　external　load　resistance　on　the　indicated　efficiency　with　cam　plate　A　is　studied.　The　results　show　that　the　intake　duration　and　exhaust　duration　have　significant　influence　on　the　motion　characteristics　and　output　performance　of　FPE-LG.　Compared　with　other　cam　plates,　cam　plate　A　(the　intake　exhaust　duration　is　60　degrees,　and　the　exhaust　duration　is　180　degrees)　can　be　considered　as　the　best　choice　for　FPE-LG.　The　external　load　resistance　not　only　influences　the　motion　characteristics　but　also　effects　the　output　performance.　The　displacement　and　velocity　increase　with　increasing　the　external　load　resistance.　The　peak　power　output　with　cam　plate　A　is　up　to　18.6　W.　The　indicated　efficiency　shows　a　downward　tendency　when　the　external　load　resistance　increases,　and　the　maximum　indicated　efficiency　of　66.2%　is　achieved.