1. A method for three-dimensional polarization-based confocal microscopy, comprising the steps of: providing a linear-polarizing structured light with a pattern; projecting the linear-polarizing structured light onto an object so as to form a plurality of beams containing focus information; performing a vertical scanning process upon the object; capturing the plurality of beams containing focus information during the vertical scanning process so as to form a series of images by a linear-polarizing imaging module; and analyzing the series of images for reconstructing the surface profile of the object.