Abstract: The plastic hinge model was adopted to represent the inelastic behavior of structural components,and based on the alternate load path method,a finite element model for non-linear progressive collapse analysis of steel frame structure was set up.The linear and non-linear progressive collapse analysis procedures were carried out for comparison.It is shown that the linear analysis can provide the decision for the weakest part of the structure with D_C index,the non-linear analysis can obtain all the damaged locations,and determine the ultimate collapse region.