Continuous　macroscopic　carbon　nanotube　(CNT)　fiber　is　made　of　meso-scale　bundles,　where　most　CNTs　are　well　aligned　along　the　fiber　axis　direction.　This　paper　presents　a　multi-scale　model　of　the　CNT　fiber　by　using　shape-based　coarse-graining　technique.　Simulations　of　monotonic　and　cyclic　tensile　tests　were　conducted　to　study　plastic　deformation　and　micro-structural　evolution　of　the　CNT　fiber.　It　is　shown　that　the　plastic　deformation　of　the　CNT　fiber　generates　after　short　elastic-like　deformation　under　tensile　loading,　and　is　closely　correlated　with　strain　rate　of　the　applied　load.　In　addition,　plastic　deformation　process　of　the　CNT　fiber　is　determined　by　different　factors　in　two　strain　rate　ranges,　i.e.　inter-bundle　interaction　at　low　strain　rates　and　mechanical　properties　of　CNT　bundles　at　high　strain　rates.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.