Abstract: Bi2O3 ceramic targets with 50 mm in diameter and 3 mm in thickness were prepared by the traditional solid-state sintering process. Bismuth Oxide films were deposited on Si(111) substrate by R F. magnetron sputtering using Bi2O3 ceramic targets. The effect of partial pressure of oxygen on the phase composition when total sputtering pressure was 0.8 Pa, and the effect of annealing temperature (350-550 ℃) on the phase composition and surface morphology of bismuth oxide films were investigated. The results indicate that with the increase of oxygen partial pressure from 0 to 0.36 Pa, the phase composition changed from BiO structure to α-Bi2O3 structure gradually. New phases appeared in films with the annealing temperature rising, but it was still multiphase structure. The full-width of the diffraction peak at half-height of different phases displayed various change. The grain size of films tended to increase with annealing temperature going up.