The invention discloses a perforated square caisson with a rear wing plate, and a structure formed by the caisson. The square caisson is characterized in that the rear wall of the perforated square caisson outward extends out of the wing edge to form the rear wing plate. By means of the perforated square caisson with the rear wing plate, and the structure formed by the caisson, wave eliminating space which is different from a wave eliminating chamber of the perforated caisson in characteristic is formed through the rear wing plate, and therefore the wave eliminating space which is in the inclined direction but not in the forward direction is formed through the structure, and the perforated square caisson better improves the effect of wave reflection in front of the structure compared with a traditional square caisson.