In order to investigate the seismic performance of reinforced concrete frame columns with post-built wing walls, low-cycle reversed loading tests toward 18 reinforced concrete specimens with post-built wing walls and finite element analysis of 675 models were completed. In the 18 reinforced concrete specimens with post-built wing walls, the test axial compression ratios of existing columns were 0.31, 0.36 and 0.40, respectively, while the longitudinal reinforcement ratios of existing columns ranged from 0.82% to 1.23%. The test and analysis results show that the wing walls are used as a energy dissipating element and reinforcing component to protect the existing column, so that the damage of existing columns with post-built wing wall are relatively damaged lightly. The damage of the 1-shaped reinforced column of the wing wall mainly occurs in the end region of the two rear wing walls. The damage of the original column of the T-shaped and L-shaped reinforced columns mainly occurs on the side of the rear wing wall and the damage area is small. The mathematical expression of the ultimate displacement angle of the wing-wall reinforced column by giving consideration to the key parameters of the existing column such as axial-compression ratio, shear span ratio, reinforcement ratio of the wing walls, etc.