Abstract: The main material of small diameter pressure spherical shell of titanium alloy, with 28 mm thick wall, is TC4ELI. According to the requirements of the design, the manufacturing process route of plate hot forming hemisphere-manual GTAW of nozzle-heat treatment of hemisphere-machining of hemisphere-vacuum electron beam welding of equatorial seam after upper and lower hemispheres closed-annealing of whole is developed and implemented. By the process, the shell is prepared and relevant tests are carried out. The results show that the dimension, air pressure, water pressure, and witness welded plates are all qualified. The sphericity, weld penetration, X-ray results, residual stress of the shell before and after external water pressure can meet the design requirements. The success of sea trial shows that the process is reliable and can provide some references for manufacturing of similar products.