Three different types of connections (dog-bone connection, bolted end-plate connection and T-stub connection) were analyzed using finite element software-ABAQUS. The dynamic behavior of connections following the column damage during progressive collapse were concluded through the analysis of load-rotation relationship when different impact loads were applied. The results showed that the forming of catenry mechanism failed during the process of progressive collapse when sufferring from impact load. And the reduced flange and bolts were the weakest parts of beam-column connections. Meanwhile, ductility method was suggested assessing the behaivor of connections. Defining the rate of ultimate rotaion capacity under impact load (θmax ) and rotation that began to form catenry (θc) as the ductility of connection. When the rate greater than 1.0, it suggested that the connection had the ability to develop catenry and the higher the rate is, the higher the security reserve capacity of the structure. This method could be used to design structures of anti-collapse economiclly and properly.