The temperature field analysis method of steel tubes reinforced columns under fire by finite element analysis software ABAQUS is proposed in this paper. The theoretical method is validated by tests, and the calculated results agree well with those of tests. On the basis of that, the influencing laws of section perimeter; steel reinforcement ratio and sectional core area ratio on temperature field are discussed. It has been found that the effects of section size and sectional core area ratio on temperature field are significant, but steel ratio has very little effect on temperature both of steel tube and of sectional center. These achievements make it possible to study further theoretical study on the fire resistance of steel tube reinforced concrete columns.