Fe 2 O 3 _ doped and undoped TiO 2 catalysts were synthesized by sol-gel method and used to optimize the photocatalytic degradation of 2,4-Dichlorophenoxyacetic acid (2,4-D). The catalysts produced were dominated by the tetragonal, crystalline anatase TiO 2 cell structure. The 0.05wt% Fe 2 O 3 _ doped TiO 2 catalyst exhibited higher photocatalytic activity than that of undoped TiO 2 but its performance decline with increase Fe 2 O 3 content due to possible increase of recombination centers. Photocatalytic degradation of 2,4-DA was optimized by response surface methodology. The highest 2,4-DA degradation (48%) was obtained when 1.0 g of 0.05wt% Fe 2 O 3 _ doped TiO 2 is used to degrade 10 ppm of 2,4-DA at pH 4.