Abstract: In order to promote the rapid determination of the quality of mongolian milkvetch root the contents of calycosin 7-O-β-D-glucopyranoside in transplanted mongolian milkvetch root from different habitats were determined by Ultra High-Performance Liquid Chromatography tandem triple quadrupole Mass Spectrometry（UPLC-MS）.The target product was extracted by methanol method with the aid of ultrasound,and Thenmo-C18（Hypersil Goldao,100 mm×2.1 mm,1.9μm）was detected by HPLC.Under the MRM mode,447/142.98 m/z and 447/284.64 m/z were used as the qualitative ion pairs and 447/142.98 m/z as the quantitative ion pairs,quantitative analysis by external standard method.The results showed that there was a good linear relationship in the concentration range of 0.018 75-0.600 00-μg·mL1（r=0.992）,the average recovery was 96.6%,RSD was 2.701%.The results showed that the content of Tongliao Naiman Banner was 0.031%,Linxi County,Inner Mongolia was 0.033% and Hohhot was 0.065%,respectively,the Hohhot was significantly higher than in Tongliao and Chifeng.The method establisbed in this research is simple,sensitive,rapid and reliable.It is suitable for the determination of calycosin 7-O-β-D-glucopyranoside in mongolian milkvetch root.