A folding box, comprising a base and two pairs of opposite side plates (30,4,5,6), wherein the base having a plate-like body and two pairs of opposite protrusion edges (201,202,203,204) surrounding the periphery of the plate-like body, and the two pairs of opposite side plates (30,4,5,6) are hinged to the protrusion edges (201,202,203,204) of the base and are foldable relative to the base, wherein a plurality of connecting parts spaced apart from each other extend from the bottom of the side plate (30,4,5,6), and at least one side plate engaging part is arranged at each of two adjacent connecting parts; pockets are formed in positions corresponding to the connecting parts in the protrusion edges (201,202,203,204) of the base, and at least two base engaging parts are arranged in each pocket, wherein each base engaging part is arranged so that when the side plate (30,4,5,6) is hinged to the base, the base engaging part is engaged with the corresponding side plate engaging part, and each side plate engaging part is arranged such that the side plate engaging part is rotatable around the base engaging part during the side plates (30,4,5,6) being folded relative to the base; and characterized in that the bottom of the side plate (30,4,5,6) is further provided with side plate limiting parts extending from the other side of the connecting parts opposite to the side plate engaging part and being a rib or a protrusion extending downward from the bottom of the side plate (30,4,5,6), and limiting grooves are formed at both sides of the pocket of the base at positions corresponding to the side plate limiting parts, wherein the side plate limiting parts are inserted into the limiting grooves respectively to prevent the side plate (30,4,5,6) from turning outwards when the side plate (30,4,5,6) is in upright state. a plurality of connecting parts spaced apart from each other extend from the bottom of the side plate (30,4,5,6), and at least one side plate engaging part is arranged at each of two adjacent connecting parts; pockets are formed in positions corresponding to the connecting parts in the protrusion edges (201,202,203,204) of the base, and at least two base engaging parts are arranged in each pocket, wherein each base engaging part is arranged so that when the side plate (30,4,5,6) is hinged to the base, the base engaging part is engaged with the corresponding side plate engaging part, and each side plate engaging part is arranged such that the side plate engaging part is rotatable around the base engaging part during the side plates (30,4,5,6) being folded relative to the base; and characterized in that the bottom of the side plate (30,4,5,6) is further provided with side plate limiting parts extending from the other side of the connecting parts opposite to the side plate engaging part and being a rib or a protrusion extending downward from the bottom of the side plate (30,4,5,6), and limiting grooves are formed at both sides of the pocket of the base at positions corresponding to the side plate limiting parts, wherein the side plate limiting parts are inserted into the limiting grooves respectively to prevent the side plate (30,4,5,6) from turning outwards when the side plate (30,4,5,6) is in upright state.