Abstract: In order to solve the welding problem between T2 copper and 316 L stainless steel,two types of BAg72 Cu solders（filamentary and paste solders） were used in the vacuum brazing. Before experiment,copper and stainless steel were chemically cleaned in order to remove the oxide film on the surface of the material,and then nickel was plated on the surface of 316 L stainless steel in order to promote the wetting and spreading of the brazing filler metal. After experiment,the performance of the joint was checked by metallographic examination and shear test.Through a series of brazing process tests,the optimum process specification was obtained. The brazed joints of T2 copper and 316 L stainless steel with shear strength above 70 MPa could be obtained at 820 ℃ and holding time of 10 min. Finally,the welding of the simulator was completed with the process parameters. The leak rate was better than 1×10^-9 Pa/（m³·s） after leak detection by helium mass spectrometry,which met the requirements of the product.