Significant creep deformation occurs on steel with the coaction of high temperature and loading, and the creep has a large effect on the deformation and load bearing capacity of steel beams in fire. In order to consider the effect of creep on the fire resistance performance of restrained steel beams, the high temperature creep model is employed to establish analysis theory on restrained steel beams by considering creep strain in the cross section of steel beam. And a computer program is performed by using MATLAB software. Restrained axial force and deflection of restrained beam under fire are analyzed by the computer program, and good agreement is found between calculation results and test data. The effect of creep on the fire resistance performance of simply supported beams and restrained steel beams is further investigated by employing the validated program. The results show that the proposed approach can accurately consider the effect of creep on the fire resistance performance of steel beams, and creep has a small effect on the fire resistant performance of simply supported beams, but has a large effect on that of restrained beams.