Abstract: A method of ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the determination of ropinirole in human plasma. The plasma samples were extracted with methyl tert-butyl ether after the addition of deuterated internal standard. The analytical column was Acuity UPLC BEH C18 column (2.1 mm×50 mm×1.7 μm), and the mobile phase was composed of methanol 10 mmol/L ammonium formate in 0.2% ammonium solution (80∶20, V/V). The flow rate was 0.4 mL/min. Detection was performed with multiple reactions monitoring (MRM) using positive electrospray ionization(ESI). The results show that the calibration curve is linear over the concentration range of 0.02-5 μg/L. The lower limit of quantification is 0.02 μg/L. Inter-day and intra-day precision are less than 15%, and the accuracy is within 85%-115%. Extraction recoveries are around 85% and the determination is independent of plasma matrix. In addition, the analyte is proved to be stable under various storage and processing conditions. Therefore, this method proves to be rapid, sensitive and specific, and suitable for the pharmacokinetic study of ropinirole in humans.