A method for merging images of an object is provided. The method includes the steps of: (a) reading the images in a storage merging all the images to form a logic rectangle rcA, and calculating a reduction scale S of the logic rectangle rcA; (b) calculating a reduction scale S of the logic rectangle rcA; (c) generating a image rcC by reducing the logic rectangle rcA according to the reduction scale S and a coordinate mapping; (d) reading all the pixel rectangles rcB; (e) reducing each of the pixel rectangles rcB according to the reduction scale S to generate an image rcD; and (f) incorporating all the generated images rcD to the image rcC according to the coordinate mapping to form an overall image of the object. A related system is also disclosed.