To establish an Ultra-High Performance Liquid Chromatography-Mass/Mass Spectrometry(UPLC-MS/MS)method to determine the contents of water-soluble vitamins in Polygoni Multiflori Radix from different habitants.Methods:The pulverized Polygoni Multiflori Radix sample was ultrasonically extracted with ultrapure water，separated by an ACQUITY UPLC BEH C18 column(2.1 mm × 100 mm，1.8 μm)and detected under dynamic multiple reaction monitoring mode(MRM)to obtain the corresponding extracted ions Flow chart，and quantified by peak area.Results:The contents of 6 water-soluble vitamins in Polygoni Multiflori Radix had great differences.Among them，the content of VB4 was the highest which was 85.89 μg/g; and the content of VB6 was the lowest which was only 0.68 μg/g.The average content of the other 4 vitamins，VB2，VB5，NA and NAM，was relatively low.Conclusion:The method is simple，accurate and reproducible.It provides a reference for the follow-up research of water-soluble vatamins and health food development of Polygoni Multiflori Radix.