To achieve the seal of the high-pressure helium gas inside round rods, a kind of a new welding device has been developed. Aiming at the special structure of the end plug and limited manufacturing demand, we analyze the main difficulties of helium seal welding. On this basis, an integrated welding chamber was designed to replace the traditional large pressure chamber and its welding set. The welding device was used to carry out application tests, and helium leakage detection and the macro metallographic tests were carried out. Finally, helium gas can be sealed in the rod sat high pressure. The welding device has the advantages of easy operation and controlled cost. It is valuable to spread and apply on other round rod devices for the high-pressure helium sealing welding.