The model incorporating different strain components of concrete and steel in high temperature has been developed to simulate the axial deformation of the wall in fire. Comparisons between the test results and the model predictions showed that the developed model was able to predict the general tendency of the axial deformation of the wall in fire. From the parametric studies with the developed model, it was found that except concrete compressive strength, both wall thickness and the ratio of the externally applied axial load to nominal strength of the wall could affect the fire resistance. Based on the results from the developed model, it was suggested that further refinement on the code provisions be made for the fire resistance to include the effect of relative magnitude of the axial load to the wall strength.