Abstract: Aim:To establish a method for the determination of sulfamethazine residues in milk by HPLC.Methods:Sulfamethazine in sample was first extracted by ethyl acetate,then defatted by n-hexane,finally determined by HPLC at 270 nm UV.Results:The lowest limit of detection was 5 μg/kg,the recoveries rate of detected samples were over 89%.