In this paper a laser triangulation scanning method for the non-contact measurement of scratches on aircraft skins and window surfaces is described. According to analyses of diffusing and reflecting properties of the measured surface, the correct setting of the laser trianglation probe is given. The adjusting posture of probe method and the spreading surface method have been developed to improve the measurement accuracy. The Scratch Depth Measuring System(SDMS) is made, It is characterized by working distance 38 mm, measuring range 5mm, simple structure as well as low cost. The experimental results are given.