AIM: To establish a Reversed-Phase high performance liquid chromatography method for determination of plasma ropivacaine in dog.METHODS:The sample was deproteinated by acetonitrile and determined with RP-HPLC and ultraviolet detection.the analytical column was Intertsil C18 column((4.6) mm?250 mm,5 ?m).The mobile phase consisted of methanol:H_2O(5050),the detection wavelength was 215 nm and the flow rate was(1.4)(ml?min~(-1)),the column temperature was 20 ℃,the sensitivity was 0.02AUFS respectively.The volume of sample for detection is 10 ?l.RESULTS:The linear range was(0.1)-25(?g?ml~(-1))(r=(0.9992)). The recovery of ropivacaine was(91.2)%-(93.6)%,RSD was(2.10)%-(3.40)%(n=6).The detection limit was(0.05)(?g?ml~(-1)).the intra-day and interday precisions of assay for ropivacaine was(1.35)%-(2.88)% and(1.80)%-(3.76)%.The quantative analysis of ropivacaine in plasma was not interfered by impurities.CONCLUSION: The assay method was shown to be suitable for determination the concentration of ropivacaine in plasma.The method is simple,accurate,sensitive and reproducible.