Abstract：In order to study the hysteretic behavior of concrete filled double skin steel tubular exposed to fire，this paper choose a reasonable constitutive model and established a reasonable finite model．Axial load ratio, time exposed to fire, strength of concrete and void ratio are the parameters of this analysis. The numerical results are verified, and the bearing capacity, hysteretic loops, and failure modes are consistent with other researchers’ experimental results. The working mechanism of hysteretic behavior of concrete filled double skin steel was investigated. The results show that: strength of concrete have little effect on hysteretic loops. But the time exposed to fire and axial load ratio affect hysteretic loops significantly. The result by analyzing hysteretic loops show that： the bearing capacity decrease with the time exposed to fire increase, void ratio decrease and axial load ratioincrease, and axial deformation get better with void ratio increase.
