Abstract: A three-dimensional finite element analysis model for square tapered concrete-filled steel tubular long columns subjected to longitudinal compression is developed and the corresponding tests are conducted． The predicted relationship curves of load versus 3 /4 height deflection，bearing capacities and failure modes have good agreements with the tested results． Based on the finite element analysis，stress and strain distribution in the whole loading process is analyzed，and interaction between steel tube and concrete is put forward． The influences of the main parameters such as slenderness ratio，eccentricity，tapered angle，have been analyzed on the ultimate loads and the relationship curves of load versus 3 /4 height deflection of square tapered concrete-filled steel tubular long columns． The results show the typical failure modes of these columns were the lateral overall bending at about 3 /4 height，the slenderness ratio，the tapered angle，the load eccentricity，the compressive strength of concrete and the steel tube wall thickness have obvious effects on their mechanical behavior，while the yield strength of steel tube has sight effect on their mechanical behavior．