Abstract: To study the dynamic performance of the welded cover plate flange connection(CWP) steel frame of resisting progressive collapse, a sub-structural detailed finite element model was established by the ANSYS/LS-DYNA software to verify accuracy of the Florea's pseudo-static tests on the middle column removal of the sub-frame. The load-displacement curves obtained from the FEM were in good agreement with the tested results, and the whole processes of the middle column removal until the sub-structure failure were well simulated. Based on the successful validation of the finite element model, the dynamic responses of steel frame beam-column substructure by sudden column removal loading mode were studied. Results show that the load-displacement curve obtained by the FEM is higher than that of energy method, while the result of FEM is closer to the real situation. The failure mode of sudden column removal scenario is close to pseudo-static test.