Abstract: Standard solution of reserpine in methanol aqueous for LC-MS calibration was developed. The puriety of reserpine powder was certified with credible methods. The standard solution was prepared by weight-volumetric method using the reserpine powder as solute and the methanol aqueous as solvent. Uniformity and stability of standard solution was analyzed by F test and regression curve method respectively, the uncertainty of the results was evaluated. The result showed that uniformity and stability of the standard solution of reserpine in methanol aqueous was better, the relative standard uncertainty of concentration was 3%（k=2）.

Key words: Reserpine, LC-MS Calibration, Standard solution