Ar+ ion beam was used to sputter the uranium film surface. Through measurement and analysis of white light interferometer and step device, the influence of sputter energy and incidence angle of the Ar+ ion beam on the surface roughness Ra of uranium film was researched, and that was compared with the etching test of Ar+ ion beam. Results show that with the incidence angle of 30o and increasing of the sputter time, the uranium film sputtered by Ar+ ion beam of 0.5 keV energy has smaller roughness and smoother surface than that sputtered by the beam of 1.0 keV energy. The sputter depth of the beam with 0.5 keV is only a few nanometers but the etching effect on Mo film is opposite. Ar+ ion beam sputter has the fine polishing effect on material surface. With the assistance of ion beam micron-sized etching thinning, it can be used for precision machining of uranium film surface.