The invention discloses a cellular SCR denitration catalyst unit hardening liquid. The cellular SCR denitration catalyst unit hardening liquid comprises, by weight, 20-40 parts of water, 10 parts of aluminum sulfate, and a proper amount of an organic acid, wherein the organic acid is oxalic acid or citric acid, and a molar ratio of the organic acid to aluminum sulfate is 4:1-1:4. The invention also discloses a use method of the cellular SCR denitration catalyst unit hardening liquid. The organic acid and aluminum sulfate are adopted as a hardening liquid and can form a complex, and the complex is uniformly distributed in a catalyst, improves the anti-wear strength of the catalyst, reduces the wear rate by 30-80%, avoids the high temperature and high dust influences of smoke gas, avoids the wear and collapse phenomenon and prolongs the life of the catalyst. The hardening liquid forms a layer of compact alumina on the top of the cellular SCR denitration catalyst after calcining, and does not realize catalyst poisoning, so the activity of the catalyst is not influenced.