The influence law of failure time and residual bearing capacity of the steel columns on progressive collapse of steel frames was studied by using a single degree of freedom (SDOF) model. The displacement of the steel frames decreases as the failure time and residual bearing capacity of the steel columns increase. On the basis of the theoretical solution of the SDOF model, boundary condition of the model was determined to consider the failure time effect. τ was defined as the ratio of the failure time to natural period of the SDOF model. For τ<0.2, the failure time can be ignored. For τ>3.0, a static method can be used to estimate the structure behavior. However, for 0.2<τ<3.0, the failure time should be considered in the progressive collapse analysis. When the resistance model is ideal elastic-plastic and rigid-plastic, the equivalent SDOF model of the steel columns can be theoretically analyzed to determine the calculation method of the failure time. Considering the deformation of the steel columns after explosion as the initial state, the calculation process for the residual bearing capacity of the steel columns is gained by combining with numerical calculations. The results show that the failure time and residual bearing capacity significantly influence on the progressive collapse of the steel frames, and those effects should be considered in the progressive collapse analysis.