Skin scratch line is a more complex problems, including the formation of surface crack and extension, continuous range of depth of cut also can form widespread fatigue damage problem, namely in cyclic load along the scratch line length direction can be a crack in multiple locations, aviation scratch tester will gradually expand, the initial crack and connected into a big crack. This paper using numerical simulation methods to analyze skin scratch line to the crack formation life influence, aviation scratch tester is used to calculate the maximum stress of the skin scratch line, and USES the local stress strain gauge to estimate the fatigue life of a given under cyclic load, we can find that: (1) when cut width is constant, with the increase of depth of cut, stress concentration factor increases gradually, the fatigue life is less, particularly if the trend in smaller scratches depth; (2) when the scratch depth of skin is fixed, the stress concentration coefficient decreases with the increase of notch curvature radius, and the fatigue life increases accordingly. The analysis method and results presented here are of certain significance to evaluate the scratch line of skin and check the threshold value. Whether there is scratch line and scratch degree of the skin can be checked by visual method after the rubber is removed, when the specific inspection can use strong light flashlight and 10x magnifying glass, aviation scratch detector and pay attention to the inspection Angle. If there is residual sealant, it should be removed by rubbing with approved solvent wetted gauze, otherwise it will cause difficulties in the inspection and evaluation of scratch lines.