Effects of metal evaporation coating on stress-strain curve of carbon fiber have been studied. D.C magnetron sputtering device was used for evaporation coating which used Nickel target and to change film thickness, sputtering time was changed. Tensile test was conducted by twisting free tensile tester. As results of experiments, the stress was little gone down, but strain was raised substantially. After tensile test, the sample was observed by FE-SEM. The Carbon was not diffusion to Nickel on the inter face.