The study focuses on the application of composite columns, utilizing four steel angles at the corners of the concrete column welded together with a transverse plate, and contrasting the experimental findings with those produced by structural analysis programs using ANSYS. Three square composite columns are included in the experimental test program under axial compression, and the primary variables are the longitudinal reinforcement ratio and steel angle thickness. Investigations are conducted into the axial and horizontal deformations, load capacity, failure mode, and axial and lateral strains of composite columns. In order to review the impact of the slenderness ratio on the behavior of composite columns for parametric study, more numerical models are utilized. The results indicate that there are two primary phases to the failure process. Localized buckling in the longitudinal reinforcement occurs in the second stage, after the concrete cover has been crushed or spalled in the first stage. The impact of steel angle thickness according to experimental results: axial strain, lateral strain, horizontal displacement, and axial displacement decrease with increasing steel angle thickness. The percentage of decrease for axial displacement is between 11% and 20%; for horizontal displacement, it is between 16% and 20%; for axial strain, it is between 4% and 10%; and for lateral strain, it is between 13% and 22%. But the load capacity increases with increasing steel angle thickness, the percentage of increase for load capacity is between 16% and 23%. The convergence rate between the analytical model and the experimental results ranged from 2% to 6% for load capacity, and 5% to 14% for axial displacement. This indicates that an analytical model that was created with the aid of the ANSYS software was able to accurately anticipate the failure load, axial deformation, and failure modes. From theparametric results obtained analytically, it can reach that with the same reinforced angle thickness, a higher slenderness ratio resulted in greater axial distortion with no impact on load capacity. This warning is particularly noticeable for columns that have smaller reinforced angles as opposed to thicker ones. If there is no obvious buckling, the influence of the column height reduces as the column height and the steel angle thickness grow. In contrast to short columns, slender columns' load capacity can be increased by increasing the thickness of the reinforcing steel angle, which also results in a greater reduction in axial distortion. Energy absorption rises with increasing slenderness ratio for thinner reinforced angles but falls with increasing slenderness ratio for broader reinforced angles.