Optical serial sectioning based on the depth-discriminating ability of a fiber optical confocal scanning microscope (FOCSM) can be combined with digital image processing to realize 3D microscopy. An instrument of FOCSM was designed for this purpose. In this paper, the 2D images of standard bars with some kinds of image processing in the FOCSM was shown. Furthermore, the in-focus image with the de-focus image has been compared, and the 2D images for the further 3D reconstruction are analyzed.