Nano Bi 2 O 3 film catalyst was prepared by sol–gel method. To increase photocatalytic activity of the films, Fe 3+ ions were doped into the films. X-ray diffraction, X-ray photoelectron spectroscopy, atom force microscopy techniques, spectrophotometer and a surface profiler were applied to characterize these films. Rhodamine B was used to evaluate the photocatalytic activity. The results show that photocatalytic activity has been improved by adding Fe 3+ ions into the films. The improvement of photocatalytic activity contributes to the increase of surface area and light utilization of the Bi 2 O 3 film.