Abstract <p>Aerospace industry demands metal joints of high quality and high strength. Dissimilar metal joint is again a challenging task since joining two metals with different physical properties is considered to be impossible. This paper portrays different metal joints of copper with stainless steel 304 which is used in the part of drive assembly of semi cryogenic engine. This combination of metal joints is extremely a field of interest among many researchers as these dissimilar joints is a complex process since the thermal conductivity of copper is too high. Electron beam welding is a good choice for this dissimilar combination. The input parameters such as beam current, welding speed, work distance are responsible for a high quality weld. Since the aircraft industry experiences high-quality defect-free weld, it is the responsibility of the researcher to optimize the best value of these input parameters. In this paper a trial has been made to join copper with stainless steel 304 by using electron beam welding. A systematic study was conducted as per Taguchi Design of Experiment (DOE) matrix with three levels of input parameters and welding is executed using electron beam welding. Hardness test and ultimate tensile strength were taken to find the mechanical strength of the weld. The best specimen is then subjected to bend test. Microstructure and SEM analysis has also been taken to find the best quality weld.</p>