Abstract: According to brazing characteristics of the thin tube-to-plate structure of stainless steel,a three-dimensional model for finite element analysis of scanning electron beam brazing (SEBB) temperature field was established.Calculated results of finite element were consistent with the experimental results,which verified the established temperature field model.The effects of processing parameters including beam diameter,scanning radius and beam current on SEBB temperature field were forecasted by means of the model.The locally uniform temperature field brazing required could be achieved by using large beam diameter,large scanning radius and small beam current.SEBB experiments of thin tube-to-plate structure were carried out by applying the optimized processing parameters from finite element analysis,and a good brazing joint was acquired.