The utility model discloses a foldable instruction book, comprising a substrate and an envelope, wherein the envelope is adhered at the middle of the substrate whose four corners and center are respectively provided with rectangle press convex lines to form four rectangles at four corners of the substrate and two rectangles at the center of the substrate, the size of each center rectangle is two powers of the rectangles at the four corners, two crossed press convex lines are provided between the center rectangles and the four adjacent corners of the rectangles at the four corners and are extended and crossed with the rectangles at the four corners and the center to form press convex lines, tow upright press concave lines are provided along the cross point of the press convex lines. When in idle, users can fold outwards along the press convex lines and fold inwards along the press concave lines to fold the concave and convex fold lines towards the substrate naturally. The foldable instruction book has the advantages of simple use and beautiful shape.