A method for enhancing the edge of a halftone image includes steps of: forming an analysis window with a central pixel and neighboring pixels; quantifying the pixels to get a halftone table; assigning a designated value to each pixel for generating a halftone result; and comparing the halftone result with an edge enhancement table. The edge enhancement table includes a plurality of dotting commands and a plurality of dot tables. The dot tables correspond to the dotting commands so that when a dot table is conformed to the halftone result, a correspondent adjustment of halftone table is taken.