Abstract: To develop a method for the determination of sulbactam in raw milk using high performance liquid chromatography-photodiode array detector (HPLC-PDA) . C18 column was used, the mobile phase consisted of 5.44g/L potassium dihydrogen phosphate solution (pH5.0) -acetonitrile (95∶5) at the flow rate of 1mL/min, the detection wavelength was 220nm.The column temperature was 30℃. Acetonitrile was used for extraction, zinc acetate was used for protein precipitation, the filtered fluid was determined by high performance liquid chromatography-photodiode array detector. The linear calibration curve was obtained in the concentration range of 1～200μg/mL (R2=0.9998) with the lower limit of detection of 0.25mg/kg and lower limit quantification of 0.75mg/kg. The average recovery of sulbactam was 98.82%～101.42%. The method was simple, accurate, reliable and could be used for rapid determination of sulbactam in raw milk.