A processor imports a 3D object, performs a 3D route slicing on the 3D object for generating printing routes respectively corresponding to printing layers of the 3D object, and performs a 2D image slicing on the 3D object for generating image files corresponding to each printing layer. The processor stores one printing route of one printing layer into a route file; stores a jetting command of the image files of the same printing layer into the route file; and stores a jetting route of the same printing layer into the route file. The processor, according to a slicing order of the multiple printing layers, stores the printing route, the jetting command, and the jetting route of each printing layer respectively into the route file, so as to complete record the route file and then outputs the route file and the multiple image files.