In order to find the optimal photocatalytic conditions for nano-TiO2,the Fe3+-doped nano TiO2powder was prepared by sol-gel method using butyl titanate as raw material.Its composition was determined by XRD.Its photocatalytic properties were examined by UV-Vis,and the effect of external conditions including light intensity,pH value and surrounding temperature was disscused.Results indicate that in a certain range,the photocatalytic activity is enhanced with the increased light intensity,and the highest photocatalytic activity is achieved when pH =4,while the ambient temperature has little effect on photocatalytic reaction.