The Fe-doped, TiO2 photo-catalyst films were deposited by reactive magnetron co-sputtering of a Ti target attached with a small slab of iron on glass substrates. The impacts of deposition conditions, including dosage of iron, sput- tering power, and oxygen level on the film growth were studied. The microstructures and photo-catalyst activity were char- acterized with X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and ultraviolet visible spectroscopy. The results show that the Fe impurity content significantly affects the microstructures and photo-catalyst ac- tivity of the films. For instance, Fe-doping roughness the film surfaces. The phase of lightly doped film was found to be anatase, whereas the iron oxide phase was observed in the heavily doped films. Fe-doping results in a transition from Ti4 ＋ in pure TiO2 films to the mixed oxidation states of Ti. The absorption edge shifts toward the visible region with increasing Fe impurity content. Though light Fe-doping improves the photo-catalyst activity of TiO2 films, heavy Fe-doping drastically reduces the photo-catalytic degradation rates of methyl orange.