In order to compare the quality differences of Mume Flos at different flowering stages,45 batches of Mume Flos at different growth and flowering stages were collected.UPLC method was used to establish a method for simultaneous determination of nine components in Mume Flos.On this basis,combined with stoichiometric analysis,45 batches of Mume Flos were identified and classified by cluster analysis (HCA),principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA).The results showed that the established method could achieve good separation of each index component in the sample,and the content of phenolic acids such as neochlorogenic acid and chlorogenic acid decreases with the increase of growth period.The contents of flavonoids such as hypericin,isoquercetin,rutin,quercetin-3-O-neohesperidin were higher in the full flowering period than in other periods.According to HCA and PCA analysis,45 batches of Mume Flos samples can be clearly divided into two categories.According to PLS-DA analysis results,it could be concluded that neochlorogenic acid,chlorogenic acid and cryptochlorogenic acid were the three components that contribute significantly to distinguish different growth stages,and could be used as the key components to guide the quality control of Mume Flos,so as to further distinguish the three flowering stages.It can be seen that the UPLC method established in this study has good accuracy.Combined with stoichiometric analysis,the method can be used to distinguish the quality differences of Mume Flos at different flowering stages and provide references for their quality control.