The invention provides a method for preparing cefquinome sulfate. The method comprises the steps: starting from 7-ACA, carrying out a reaction with tetrahydroquinoline in dichloromethane and with hexamethyl-disilazane as a protective agent, trimethylchlorosilane as a reaction catalyst, diethyl aniline as a reaction system polarity regulator and dimethylacetamide as a tetrahydroquinoline dispersion medium, after the reaction is completed, dropwise adding a 25% aqua ammonia, growing crystals, washing and filtering with acetone, and thus obtaining a pale yellow intermediate 7-ACQ; carrying out a reaction of the intermediate 7-ACQ and an AE active ester in an inert organic solution with a small amount of ethanol as a dispersant and sodium metabisulfite as an antioxidant, neutralizing an acid continuously produced in the reaction by adopting triethylamine as an acid binding agent, after the reaction, washing and filtering with a dichloromethane and ethanol mixed solution, then extracting with pure water for multiple times, adjusting the pH with sulfuric acid, controlling the temperature to crystallize, and thus obtaining a crude product; and then washing, filtering and recrystallizing the crude product to obtain the refined cefquinome sulfate. The product has the advantages of high conversion rate, good purity, good color and luster and the like.