Disclosed is a collapsible box, comprising a base (1) and two pairs of opposite side plates. A protrusion edge (10) is provided at the periphery of the base (1). The side plates are hinged to the base and foldable relative to the base (1). Each of the side plates is smooth at both sides thereof and at least one pair of the side plates are each provided with a cavity in lower edges. When a collapsible box (100) is deployed, the lower edges of one pair of side plate are connected with the lower edges of the other pair of side plates so as to form a frame. The frame is hinged to the base (1) by means of hinges, so as to form a reinforced structure which resists the base from depressing and the protrusion edge from recessing. This solution increases the cleaning efficiency of the collapsible box, alleviates the depressing of the base when the box body is loaded, and solves the problem of the collision and damage among goods in upper and lower layers due to the depressing of the base due to multi-layer stacking of collapsible boxes. Further, the safety risk in warehouse storage caused by the failure of stacking due to side plate deformation caused by multi-layer stacking of collapsible boxes and side plates being pressed is avoided. Meanwhile the box has a smaller wall thickness and a higher folding ratio.