A digital halftoning method and a method for constructing a class tiling map are disclosed. The present invention utilizes to arrange class matrixes in a staggering form such that adjacent class matrixes exist a staggering shift. Also, the class tiling map is constructed in this way. Then, a dot diffusion procedure is performed to an original image with the class tiling map so as to generate a halftone image corresponding to the original image. The present invention is capable of solving the problem of a periodic appearance caused by traditional dot diffusion.