Abstract: The commercial denitration catalyst V₂O₅-WO₃/Ti O₂ poisoned by potassium（K） was prepared by impregnation method. Meanwhile, experiments were conducted to investigate the regeneration of denitration catalyst V₂O₅-WO₃/Ti O₂ poisoned by K with oxalic acid. The results show that the regeneration effect is best and the regenerated catalyst regain more than 97% of its initial activity when the oxalic acid concentration is 0.001 mol/L, generation time is 30 min and temperature is 60 ℃.The structural characteristics of catalysts before and after regeneration were characterized by Brunauer-Emmett-Teller measurements（BET）, Fourier transform infrared spectroscopy（FT-IR）, Infrared spectroscopy measurements of NH₃ adsorbed on catalysts（NH₃-IR）, Hydrogen temperature-programmed reductions（H₂-TPR）, X-ray photoelectron spectroscopy（XPS）. The results show that K on the surface of the poisoned catalysts could be efficiently removal by oxalic acid. The specific surface area and the Br?nsted acid sites of poisoned catalysts could be restored effectively by regenerating with oxalic acid. Moreover, by regenerating with oxalic acid, there were no harmful residues on the surface of the catalysts poisoned by potassium.