Abstract: The anatase/rutile mixed-phase TiO₂ powders were prepared by sol-gel method and the crystal structure, surface morphology and element composition of the samples were tested. The effect of heat treatment on anatase/rutile weight ratio of the mixed-phase TiO₂ and their photocatalytic properties were also studied. The experimental results show that the increasing heat treatment temperature and holding time can enhance the content of rutile phase and promote the transformation from anatase to rutile. The photocatalytic property of mixed crystal TiO₂ is higher than that of single anatase or rutile TiO₂. The sample heat treated at 550 ℃ for 3 h shows the best photocatalytic activity which consists of 40% anatase and 60% rutile. The degradation rate of rhodamine B is 84.1% after 3 h.