Abstract: Based on the analyses of earthquake failure,the failure experiment on four full-size specimens of steel frame beam-column welding connections under cyclic loading is accomplished,taking account of influencing factor in form of scallop structure.According to a comparison of moment-plastic corner cure with moment-cumulative plastic deformation multiple cure,the test results show that scallop structure and steel tab are the primary factors influencing the plastic deformation capacity and failure mode of beam-column connections.Improving the scallop structure is an effective means,which can improve not only the aseismic behavior but also the construction technique is the same as the traditional connections.