A high performance liquid chromatographic method was developed and validated for the quantitative determination of catechin in rat plasma and its pharmacokinetic study after intragastric administration of Catechu and Xiongdanjiangre Wan into SD rats. Plasma samples were prepared by protein precipitation using methanol-5% aqueous zinc sulfate （70：30, v/v） as precipitant. Chromatographic separation was achieved on Hypersil Cl8 column （250 mm~ 4.6 mm, 10 pm） with acetonitrile-water-triethylamine （6：94：0.3, v/v/v, pH 4.0＋0.1, adjusted with phos- phoric acid） as mobile phase, followed by a UV detection at 207 nm. Good linearity was obtained over the range of 0.143-7.15 mg/L of catechin, with correlation coefficient of 0.9992. The method was simple, sensitive, accurate and reproducible and＇ has been successfully applied to the pharmacokinetic study of catechin in rat plasma.