The invention relates to a method for changing the soft-covered book into hard-cover book, which comprises three steps as processing book core, processing book cover, and mounting the book cover. Wherein, first, removing the cover of soft-covered book; then making holes, binding, preparing annular liner, adhering block cloth, adhering gauze, adhering book back paper to complete processing the book core; the second step is that adhering the cover on the white paper, then flattening the coat film, cutting the front and back seal, and the middle paper sheet, then folding edge and packing corner; the third step comprises pressing groove, adhering annular liner and flattening. The inventive method can overcome the defects of present technique, with simple operation and lower cost.