Abstract: The structures of the joints of the concrete filled tubular frame structure are complicated. So far, researches on the mechanical performance of certain types of joints are not enough and there is no specification or code which could address this issue. Thus, it is the necessity to study thoroughly the mechanical performance of the joints. In this study, finite element software ANSYS is introduced to conduct researches on the mechanical performances of the joints. Then the function and setting principles underpinning the stiffened plate are discussed. Results show that, the joints have good bearing capacity that can meet the requirements of the relevant provisions, and stiffened plates can effectively improve the mechanical performance of the joints.