In this work, the projected range, the nuclear stopping power(Sn), electronic stopping power (Se), vacancies, replacement collisions, and total target damage of β-Ga2O3 by H, He and Ar ion bombardment are investigated by the Monte Carlo SRIM software. The ions were vertically incident on a 1-um β-Ga2O3 material, and their energies varied from 100 keV to 1 MeV. The results showed that the projected range increased for all three ions with increasing incident energies, with H ions having the largest projected range. The Sn for Se with incident energy of 0-1MeV in β-Ga2O3 is much greater than the Sn for H and He, while the Sn for Ar decreases gradually with the increase of incident ion energy, and the Se shows a gradual increasing trend. Compared with H and He, the number of vacancies induced by Ar were the largest at the same incident energy and thickness of β-Ga2O3. In addition, it is obvious that the total target damage of Ar on β-Ga2O3 material were much more serious than H and He.