Aiming　at　handling　the　contradiction　between　power　constraint　of　on-orbit　manufacturing　and　the　high　energy　input　requirement　of　metal　additive　manufacturing　(AM),　this　paper　presents　an　AM　process　based　on　small-power　metal　fine　wire　feed,　which　produces　thin-wall　structures　of　height-to-width　ratio　up　to　40　with　core-forming　power　only　about　50　W.　In　this　process,　thermal　resistance　was　introduced　to　optimize　the　gradient　parameters　which　greatly　reduces　the　step　effect　of　the　typical　AM　process,　succeeded　in　the　surface　roughness　(Ra)　less　than　5　mu　m,　comparable　with　that　obtained　by　selective　laser　melting　(SLM).　After　a　10　min　electrolyte-plasma　process,　the　roughness　of　the　fabricated　specimen　was　further　reduced　to　0.4　mu　m,　without　defects　such　as　pores　and　cracks　observed.　The　ultimate　tensile　strength　of　the　specimens　measured　about　500　MPa,　the　relative　density　was　99.37,　and　the　Vickers　hardness　was　homogeneous.　The　results　show　that　the　proposed　laser-Joule　wire　feed-direct　metal　deposition　process　(LJWF-DMD)　is　a　very　attractive　solution　for　metal　AM　of　high　surface　quality　parts,　particularly　suitable　for　rapid　prototyping　for　on-orbit　AM　in　space.