Drum line according to certain Angle inclined fixed on the shelf beam, pallet from high-end into, along the drum line by itself gravity down, in order to control the tray to stabilize speed glide, avoid impact, in roller online every distance setting a damping system, pallet glide speed faster, damping system to produce the greater resistance. End part from institutional setup at the low end, used to separate minimum at the two tray, so that the most low tray can take out smoothly. Gravity shelf space utilization rate is higher than the press in type shelf and racking, and realize the "fifo" principle, safety and operation efficiency and pressure into the same type shelf, widely used each industry.