The present invention relates to a display rack which can automatically replenish the products in the front of the rack. The display rack comprises: a rack, an auto-tracking system, a sliding unit and a smooth surface. One end of the auto-tracking system is connected to the front plate of the rack and the other end of which is connected to the vertical plate of the sliding unit. The sliding unit is placed inside the rack and is able to slide freely. The smooth surface is on the inner bottom surface of the rack to reduce the sliding unit's resistance while sliding.