The invention discloses a regeneration fluid for an SCR denitration catalyst, which comprises the following components: 0.001 to 1 weight percent of penetration enhancer JFC, 0.001 to 1 weight percent of surfactant OP-10, 0 to 1 weight percent of peregal, 0.6 to 4 weight percent of ammonium metavanadate, 5.5 to 12.5 weight percent of ammonium paratungstate, 0 to 6.5 weight percent of ammonium paramolybdate, and the balance of deionized water and acid. The regeneration fluid has the advantages that the regeneration fluid can also supplement active ingredients during the washing, and the activity recovery of the catalyst after the regeneration is up to between 90 and 105 percent; a nonionic surfactant is added into the regeneration fluid, so that the regeneration fluid improves the cleaning capability on the catalyst and cannot cause the damage to a catalyst carrier and other effective ingredients; and the regenerated catalyst fully can continue to be normally used, and the service life can reach more than 95 percent of that of a new catalyst.