Plug modular structure, the standard set of plug member without a link bolt, easy installation and removal fast, laminates for the cutting, folding processing from the super-closed steel laminates, laminates have the following spot welding stiffeners or supplementary slugger, the height is adjustable every 50 cm, shelf unit on each floor load up to 400 kilograms, square column, front punching a small number, so that the shelf is more stable and elegant.