Abstract: In order to study the elas to plastic response of the beam to column welded connection under the seismic load and improve the earthquake resistant performance of welded joint,the non linear FEM analysis of "H" and "Dog Bone" Type of welded connection under the simulating seismic cyclic load was carried out by utilizing the ANSYS programming package.The von Mises equivalent stress of welded joint and the hysteresis loops were obtained.The dissipative coefficient was introduced and used as an index to evaluate the dissipative capacity of the welded connection under the seismic load.The dissipative coefficient of two types of welded connection was computed and the results indicated that the earthquake resistant performance of the "Dog Bone" connection was better than that of the typical welded connection.