The invention discloses a method for preparing cefquinome sulfate, belonging to the cephalosporin antibiotics special for animals. The method comprises the following: A. a step of preparing 7-amino-cefquinome, during which, iodotrimethylsilane reacts with 5, 6, 7, 8-tetrahydroquinoline, and a reaction product reacts with 7-amino-cephalosporanic acid, thereby obtaining the 7-amino-cefquinome; B. a step of preparing the cefquinome sulfate, during which, the 7-amino-cefquinome reacts with AE active ester after the 7-amino-cefquinome is dissolved and is decolored by sulphuric acid, and the cefquinome sulfate is obtained after the reaction product is subject to extraction, suction filtering, leaching and drying. The method uses 7-ACA which is widely used in industry, is low in cost and is easily obtained as a raw material, without using cefotaxime acid with unstable service quality; meanwhile, the method has a mild reaction condition and simple operation, reduces the dosage of the 5, 6, 7, 8-tetrahydroquinoline which is an important intermediate, and greatly improves the product quality with the yield of 64.1 percent and the purity of 99.7 percent, thereby the method is suitable for industrial production.