A paperboard includes a rectangular main portion, and first and second foldable extension parts respectively extending from four sides of the main portion. The main portion is divided by fold lines to form a first region and two second regions on two sides of the first region. The paperboard is foldable to form a first packaging configuration in which a four-sided surrounding wall extends upright from the first region, or a second packaging configuration in which one side of the four-sided surrounding wall is unfolded. A plurality of soft plates are respectively provided on the first region, and four sides of the surrounding wall for cushioning purposes.