Abstract: A quantitative method of analysis of multi-components by single marker (QAMS) method for the quantification of six polyphenols in quinoa was established, and 6 polyphenols in 5 kinds of quinoa were compared. Samples were analyzed by ultra performance liquid chromatography (UPLC) system, equipped with a ACQUITYUPLC®BEHC18 (2.1 mm×50 mm, 1.7 μm) chromatographic column, with the mobile phase of methanol-0.2% glacial acetic acid solution at a flow rate of 0.2 mL/min. The column temperature and the detection wavelength were set at 35℃ and 247 nm respectively. The isoorientin was used as the internal reference to determine the relative correction factors (RCFs) of other five components, and their contents were calculated by their RCFs at the same time, and then compared with the external standard method (ESM) by SPSS software. No significant differences were found in the quantitative results of six polyphenols in 5 varieties of quinoa determined by ESM and QAMS (p>0.05). The contents of isoorientin, caffeic acid, p-coumaric acid, ferulic acid, rutin and quercetin in the five quinoa species were 210.34~370.61, 3.77~8.04, 168.86~300.21, 10.98~17.15, 31.13~42.75 μg/g, respectively. It was feasible and suitable to evaluate the quality of quinoa by QAMS with isoorientin as the internal reference.