Abstract: Vacuum electron beam welding is the main method of preparing extra-thick slab, but the research on whether there is N content loss in the weld and whether it affects the performance of the product is rare. S32101 economical duplex stainless steel was welded by vacuum electron beam welding. The microstructure observation, tests of N content, z direction tension and Charpy impact property of welded joints in welded and post-weld hot rolled solid solution states were carried out.The results show that the content of N in S32101 vacuum electron beam weld decreases obviously compared with that of the base metal. However, the mechanical properties of the weld after rolling and solid solution are equivalent to the rolled composite surface, and cutting is not required during delivery. Because the weld area with low N content is located in the center of the plate thickness and will not contact with the corrosive medium, its corrosion resistance is not required to be considered.