| In order to adapt the emerging of new construction and bridge structures and so on, the concrete filled steel tubular (CFT) structures are widely applied in modern civil engineering by its superior anti-seismic behavior and strong capacity of resistance compression.This thesis is mainly to the dynamic behavior experiments, considered different axial compression ratio, sectional steel ratio and slenderness ratio, under combined constant axial load and cyclic lateral load on six the concrete filled square steel tubular (CFSST) columns. And the influence of each parameter on CFSST test component's behavior of earthquake resistance are analyzed by analysing the experiment and results. In order to research the changes situation of test component's resistance compression capacity and rigidity, skeleton curves and the rigidity curves are analyzed. Compare with the reinforced concrete structures and steel structures, the CFT structure bearing capacity drops relatively gentle after yield, and the rigidity didn't drop obviously until the angle of displacement beyond 1/100.Load-deformation hysteretic curves of the CFSST are calculated by the numerical method, and the numerical calculative results are in better agreement with the tested curves. The ductility coefficient of the CFSST are calculated based on the restoring model, and influence of parameters such as slenderness ratio, axial compression ratio, sectional steel ratio, steel products yield strength and concretes compressive strength are analyzed.At the aspect of bending components'supporting capacity equation development, It had merely considered the restraint cuff function of square steel tubular to inter-filled concrete macroscopically, without the influence brought by steel tubular section's flexure, therefore, it is still have certain deviation when compared with the test result.
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