Abstract: To carry out studies of the local scour around the bridge piers under different discharges, a multi-level structure is formed by increasing anti-scouring plates in addition to a single anti-scouring plate. A principal component analysis is made of anti-scouring indexes by multivariate statistical methods. It has proved the maximum pit depths have a great reflection of experiment results. In addition, the experiment results are analysed using the maximum pit depths. The analysis results show that the anti-scouring effect can′t be improved by increasing the anti-scouring plates at 75 m3/h, but it can be increased at 115 m3/h. Besides, the anti-scouring effect increases with decrease of the spacings between the anti-scouring plates, and enhances with increase of the outer diameters of the anti-scouring plates. However, the anti-scouring effect of three-level anti-scouring plates is similar to that of the two-level anti-scouring plates. The third-level anti-scouring plate has little effect on the experiment results. Therefore, under the conditions of different discharges, the optimal structure of the ring-wing anti-scouring plates will be two slices of the anti-scouring plates. The outer diameter of the anti-scouring plates is 180 mm, and the spacing between the anti-scouring plates is 15 mm.