Despite the excellent engineering properties of concrete filled tubs (CFT), they are not as widely used as traditional structural steel and reinforced concrete members. The aim of this study was to predict the buckling behavior of concrete-filled steel hollow structural section beam columns with advanced finite element methods and compare the predictions with experimental results and optimize findings and represent a finite element model for further studies. A total of 2 different specimens from the experimental study were investigated with eccentric loading and ABAQUS software is used for modeling and non-linear analysis. The specimens have square section with overall depth of 120 mm and 140 mm respectively and the thickness for all sections was 3.84 mm. The tests were performed on pin-ended Beam-columns. It is found that load could carried by concrete filled steel tube with size of 120 mm, increased about %44 in compression of steel tube section also, it increased about %108 in compression of reinforced concrete section with %3 of longitudinal rebar.