Abstract: The beam joints of concrete filled steel tuble(CFST) and the forced analysis are the key technique for the study and application of CFST structure. Due to the importance of the constitution and performance under loads of beam joints of CFST column, many experimental studies were carried out. According to a column joint which has steel brackets through tubular core, a nonlinear 3D-FEM is presented in Ansysusing the combined reinforced model and smeared cracking model. Under vertical and symmetrical load case the stress distributions and the mechanism of internal force transmission in the joint are studied. The well-agreement between experimental data and calculated result show that the FEM model accurately revealed the performance of the joint. According to the analyses, some advice is given to improve the joint constitution.