Removing column is a method to analyze the progressive collapse of str uctures. Different models that simulate the process of removing column were comp ared in this paper. These models were classified into 9 kinds according to the d ifference of loading steps, dynamic amplifying factors, and strain rate effects and so on. A space steel frame with 10 stories and 3 spans was analyzed by the f inite element method using the 9 models, and the displacement and reaction results were compared. The differences and deficiencies of these models were analyzed based on the above results. Moreover, the effects of magnitude and loading dura tion of the impact loading on response of the example in this paper were analyze d.