Abstract: Based on the finite element method,the interactive buckling of tapered H-section steel beams used in portal frame structures are analyzed by ANSYS,in which geometric and material non-linearity are considered.The H-section tapered beams with thin web are dispersed by Shell 181 element and analyzed considering the geometric initial imperfection and the residual stress in the whole course.According to the load-deflection curves obtained,ultimate load-carrying capacity,deformation and the area of plasticity etc,the geometric parameters are analyzed systematically,which include web width-thickness ratio,flange width-thickness ratio,span and web tapering ratio etc.The interactive buckling of tapered H-section steel beams is discussed.By comparing the results obtained from the method with those of current Chinese technical specification,some valuable conclusions are drawn.