A method for improving the anti-fatigue performance of a carbon fiber composite material by introducing carbon nano tubes from the interface includes the concrete steps that the functional carbon nano tubes are introduced into surfaces of carbon fibers, and then a carbon nano tube-carbon fiber multiscale reinforced resin composite material is prepared through composite molding. According to the method, the carbon nano tubes are fully used for reinforcing and toughening resin matrixes in interface micro areas, a barrier for resisting formation and expansion of fatigue cracks is built on the interface to delay direct attack on the fibers by the cracks, and the fatigue service of the composite material is prolonged. Compared with a traditional fiber composite material prepared from the carbon nano tubes and resin through a blending method, the carbon nano tubes in the carbon nano tube-carbon fiber multiscale reinforced resin composite material can be evenly dispersed more easily and are small in usage amount, and the multiscale reinforced resin composite material is wide in suitable molding technology range and has the advantages of being low in cost, suitable for industrial production and the like.