Tin dioxide thin films were prepared by a direct photochemical vapour deposition method. The raw material was tin(II) acetate. A 6 W low-pressure mercury lamp was used as a light source. At a substrate temperature above 150-degrees-C, the thin film was obtained in air with a deposition rate which is higher than that for thermal chemical vapour deposition. UV irradiation without premixing oxygen gas improves crystallinity, suppressing the intrusion of carbon contamination.