Abstract: The problem of the multiplication nuclear material and transformation nuclear waste is studied by ADS Injector.The vacuum chamber for ADS Injector thermostat is designed by theoretic calculate-on and numerical simulation in this paper.The internal dimensions of the rectangular vacuum chamber are 4 200 mm×1 500 mm×1 500 mm.According to requirements of the sealing performance and the struct-ural strength，the structural design of the vacuum chamber welding line introduced.In accordance with requests of dimension precision and stability，the paper finally introduced manufacture technology of va-cuum chamber.The performance of thermostat can meet the design requirements after testing.