Abstract: HPLC was applied to the determinations of 3 sulfonamides in prawn, including sulfadiazine (SD), sulfapyridine (SPD) and sulfathiazole (ST). The sample was extracted by acetonitrile, and the extract obtained was purified by defatting with n-hexane. The Hypersil ODS column (250 mm×4.0 mm, 5 μm) was used as stationary phase, and a mixed solution of methanol and water (mixed in the a ratio of 25 to 75) was used as mobile phase. The eluate from column was used for HPLC analysis with UV detector. External standard calibration was adopted in the determination. Linear relationships in definite ranges between the values of peak area and mass concentration of the 3 sulfonamides were obtained. The values of RSD′s (n=6) and recovery found by standard addition method were 93.0% and 3.1% for sulfadiazine , 89.9% and 0.1% for sulfapyridine, 88.7% and 1.1% for sulfathiazole respectively.