Abstract: The ion gun generates Ar ion beams with well defined space and energy distribution.It is composed of ion source, extraction grid, collimator lens structure and electronics controller.It is an important equipment in surface science and nanotechnology, which provides a means to sputter or etch a surface and generates an elemental or chemical depth profile. In this article, a domesticAr ion gun with 2 kVbeam voltage and 4.5 μA beamcurrent is introduced.