To make 3D visual texture effect of surface with bare eye in the plane thickness of micron-level, based on Fresnel optics principle, for conventional free-form surfaces, the continuous surface “collapse” method of reducing the thickness of the Fresnel lens is prone to large areas of visible segmentation planes and the problems that the visual effects of the designed micro-textures are difficult to predict. In this paper, a unit texture construction method is proposed, which differentiates the free-form surface into square mesh cells whose size is smaller than the smallest size that can be recognized by human eyes. The micro-surface in each element is approximately treated as a square column with inclined plane at the top, and the normal vector of the inclined plane is close to the synthetic normal vector of the micro-surface. Then, according to the limit of the design thickness, the inclined plane column is “collapsed” to ensure that one end of the inclined plane touches the bottom, and the height difference of the inclined plane in the unit is less than the designed thickness. Finally, the light source is set for the completed gray image file. The brightness of each point in the image file is inversely proportional to the angle between the point normal vector and the light source, and the visual dynamic rendering effect of the overall scheme simulation is obtained by rotating the light source. The validity of the proposed method and the effectiveness of the simulation results are verified.