A sharpness processing method and system for a digital image are applied to an image capturing device for capturing a raw image. The method includes the steps. An image processing procedure is performed on the raw image to generate a registered image. A first sharpness enhancement table and a second sharpness enhancement table respectively sharpness attenuation at an outer-edge region and a central region of the registered image are loaded, and a range between the outer-edge region and the central region is defined as a plurality of critical regions. A sharpness enhancement weight table is loaded, and weight values of each critical region respectively corresponding to the first sharpness enhancement table and the second sharpness enhancement table are searched, for obtaining a sharpness enhanced value of each critical region. An image sharpness processing procedure is performed on the critical region, for correct the registered image into a digital image.