Abstract: The multi_stage vacuum diffusion chamber and the guide tubes have been chosen to limit the propellant of the 30 barrels pellet injector for entry into the vessel of HL₂A tokamak. This design mainly depended on the load of the propellant during pellet injection and met the requirments of fuelling experiments from the low magnetic field side (LFS)to high magnetic field side (HFS)of HL₂A. The vacuum load,the structure of the guide tubes and the pumping system for 30_barrels pellet injector were introduced.