TiO2 fibers were successfully synthesized by ACF template method. The structural and electronic properties were examined by using FE-SEM, TG/DTA, XRD, BET, EDX and XPS spectroscopy. TiO2 fiber has a uniform diameter of 5-10 mum and rough surface. Ti precursor, ratio of Ti/ACF in preparation step and calcinations temperature of TiO2 fibers were optimized for the photocatalytic application. The TiO2 fiber which was prepared by using 15% Ti(SO4)(2)/ACF solution and calcined at 773K showed the highest photocatalytic activity for the decomposition of acetaldehyde. The photocatalytic performance of TiO2 fiber was higher than the commercial TiO2 (Degussa P-25) because of its large surface area, high crystallinity and acid sites.