In order to improve the efficiency of modern manufacture and meet the requirement of 3D scanning, a scanning system which can accurately extract 3D contour information of object surface is designed. The 3D imaging method of structural light is adopted. Firstly, the grating is projected to the surface of the object under testing by ordinary white light, and the distorted raster image is collected by industrial camera. Secondly, the 3D coordinate information is extracted by Fourier transform contour method according to the change of gray value in the image of deformation raster. The experimental results show that the reconstruction of the three-dimensional point cloud with ideal effect can be achieved by using the Fourier transform contour method,which provides an experimental method for the 3D contour scanning and a reference basis for the precision of the high point cloud.