Titanium dioxide is one of the best semiconductor photocatalysts available for photocatalytic reaction of dye pollutants. To prevent the recombination caused by the relatively low photocatalytic efficiency, Ag doped TiO(2) nanofiber was prepared by electrospinning method. The photocatalysts (pure TiO(2) nanofiber and Ag doped TiO(2) nanofiber) were characterized by FE-SEM, XRD, XPS, and PL analysis. These photocatalysts were evaluated by the photodecomposition of methylene blue under UV light. Ag doped TiO(2) nanofiber was found to be more efficient than pure TiO(2) fiber for photocatalytic degradation of methylene blue. The photocatalytic degradation rate was applied to pseudo-first-order equation. The degradation of Ag doped TiO(2) nanofiber was significantly higher than the degradation rate of pure TiO(2) nanofiber. Activation energy was calculated by applying Arrhenius equation from the rate constant of photocatalytic reaction. The activation energies for the pure TiO(2) nanofibers calcined at 400 and 500 A degrees C were 16.981 and 12.187 kJ/mol and those of Ag doped TiO(2) nanofibers were 18.317 and 7.977 kJ/mol, respectively.