Pure and Pd-doped ZnO nanofibers were synthesized via an electrospinning technique, in which polyvinylpyrrolidone was used as the fiber template, zinc acetate/palladium chloride as the precursors, and a mixture of ethanol/acid acetate/water at ratio of 8:5:2 (v/v/v) as the co-solvent. The electrospun fibers were calcined at 600 A degrees C in air for 2 h and characterized by various methods. The photocatalytic activity of the pure and Pd-doped ZnO nanofibers was studied through the photodegradation of methylene blue. Comparing to the pure ZnO nanofibers, the Pd-doped catalysts showed a much enhanced photodegradation efficiency. The possible mechanism was also discussed.