Objective:To establish a measurement method for determining the levels of monoamines neurotransmitter and their metabolites in rat plasma by HPLC with Coularray Detector-2．Methods:The levels of NE，E，DA，HVA and 5-HT in rat plasma were determined by Agilent 1200 HPLC with ESA Coularray Detector-2．Mobile phase consisted of 80 mmol·L-1 Citric acid monohydrate，73.4 mmol·L-1 Citric acid trisodium salt，0.12mmol·L-1 1-Octanesulfonic acid sodium salt

0.1 mmol·L-1 EDTA-Na2 and 18% methanol mixture solution(pH4.3)．Flow rate was 1.0 mL·min-1 The Column was Zorbax Eclipse XDB-C18(4.6 mm X 150 mm，5 μm)and Easyguard guard column at 25℃．The voltage of electrode was -150 mV and 400 mv．Results:The minimum measurement limit of NE，E，DA，HVA and 5-HT were 2.0，3.0，5.4，5.2 and 11.1 ng·mL-1 respectively．The average recoveries were 99.72%，85.33%，83.15%，120.43% and 103.56%，respectively．The RSD of intra-day(n=6)and inter-day(n=3)were less than 9.12%．Conclusion:The method was easy to operate，rapid，accuracy and high in sensitivity，and could be applied in quantitative determination and study of monoamines neurotransmitters and their metabolites in rat plasma．