Carbon　nanotube　(CNT)　wire　is　a　hierarchical　material　made　by　braiding　fibers　or　yarns　of　CNTs.　In　this　work,　tensile　experiments　were　conducted　to　investigate　the　elasto-plastic　deformation　and　fracture　mechanism　of　the　five-yarn　wires.　The　stress-strain　curves,　and　accordingly　the　Young＇s　modulus,　ultimate　stress　and　strain,　of　the　CNT　wires　at　different　strain　rates　were　obtained.　The　plastic　aspect　of　the　CNT　wires　was　emphasized.　Then　influence　of　the　strain　rate　on　the　mechanical　performance　of　the　CNT　wire　under　monotonic　and　cyclic　tensile　loadings　was　explored.　Morphologies　of　fractured　surfaces　and　micro-structural　damage　mechanisms　of　CNT　wires　with　the　variation　of　strain　rates　were　discussed　based　on　scanning　electronic　microscopy　images.　It　is　shown　that　the　CNT　wires　have　Young＇s　modulus　of　1.38　GPa,　the　yield　limit　of　6.93-8.99　MPa,　the　quasi-static　strength　of　124.4　MPa　and　ultimate　strain　of　0.153　mm/mm.　And　they　are　affected　by　the　strain　rate.　Under　both　monotonic　and　cyclic　tensions,　the　fracture　mode　of　the　CNT　wire　exhibits　a　ductile　mode　at　comparatively　low　strain　rates　and　a　brittle　mode　at　comparatively　high　strain　rates.　(C)　2016　Elsevier　Ltd.　All　rights　reserved.