Abstract: When the W/t ratio is large in square concrete filled steel tubes, the part disability of the section due to local buckling of steel plates should be considered. Reinforcing ribs can help to solve this problem. The buckling coefficient k is analyzed by varying diameters of the steel plate with ribs, and the influence of the dimension of the reinforcing ribs is obtained. Two conditions should be satisfied when choosing ribs. The process and checking method of arranging the ribs in large W/t ratio columns are also given.