The present disclosure discloses a packing box in the field of outer packing technique in view of problems that the existing thick packing box occupies large space in transporting and storage and cannot be reused after disassembled due to adhering connections. The packing box includes two cover bodies configured to snap one another, each of the cover bodies is formed by a folded plate member, and the plate member includes an internal flexible layer, an external flexible layer and a paperboard layer therebetween, where the cover body includes a bottom plate, and a side plate and a flipping plate both arranged on each of opposite sides of the bottom plate, one side of the side plate is connected to the bottom plate, and the other side of the side plate is connected to the flipping plate, so that the side plate is foldable with respect to a side edge of the bottom plate that is connected with the side plate, and the flipping plate is foldable with respect to a side edge of the side plate that is connected with the flipping plate. A locating structure is arranged between the bottom plate and the side plate, and a free end of the flipping plate is configured to be inserted and fixed to the locating structure. Since adhering connections are avoided in the assembling of the packing box, the production efficiency is increased, and the packing box is easy to disassemble and assemble and may be reused, so that the cover body can be disassembled to save space for transporting and storage.