Coarse-grained　molecular　dynamics　simulations　have　been　performed　to　investigate　the　tensile　behavior　of　CNT　films.　It　is　found　that　CNT　entanglements　greatly　degrade　the　tensile　load-bearing　capability　of　CNT　films.　The　effect　of　twisting　on　the　tensile　behavior　of　CNT　fibers　spun　from　CNT　films　has　also　been　investigated.　Results　indicate　that　twisting　can　make　either　positive　or　negative　contributions　to　the　mechanical　properties　of　the　film,　depending　on　the　microstructure.　The　structural　and　energy　evolution　of　CNT　films　and　fibers,　as　well　as　the　stress　distributions　of　CNTs　which　cannot　be　easily　determined　experimentally,　have　been　illustrated.　This　study　provides　an　effective　means　of　revealing　the　structure/property　relationships　of　CNT　films/fibers,　which　are　essential　in　designing　high　performance　CNT　fibers.