A new method to reconstruct embossment three dimensional (3D) shape ba sed on microscopic imaging sharpness is proposed.In this method,a sinusoidal grating is projected onto t he stage by a projector coupled from the microscopic eyepiece pupil through a objective with 5× magnification,the fringe images in different defocus distances are captured by CCD with moving a proper step along Z axis,so th e imaging sharpness to height look-up table can be built by calculating the normalized curve between the imaging sharp ness and defocus distances with variance sharpness evaluation function. Then the measured embossed object is pla ced on the stage and the corresponding deformed fringe is captured by CCD,the fringe areas at different sharpness are extracted by image segmentation algorithm.By calculating these segmented fringe imaging sharpness, the heights in different areas can be known according to the look-up table,finally the embossed object on can be successfully reconstructed. Its feasibility is demonstrated by simulation,and its effectiveness is proved by 3D shape reconstruction experiment of the number “0” in a coin with the error range from －2μm to 2μm.