Objective To investigate the chemical composition from the flowers of Callerya speciosa,and reveal the metabolites difference at different flowering periods based on metabolomics technology.Methods The primary and secondary metabolites,volatile chemical components in flowers of C.speciosa were analyzed combined by GC-MS and UPLC-Q-Exactive MS.Principal component analysis(PCA),orthogonal partial least squares-discriminant analysis(OPLS-DA),and hierarchical cluster analysis(HCA)were performed to identify differential metabolites.Results A total of 332 compounds were identified by UPLC-Q-Exactive MS,mainly including secondary metabolites such as flavonoids,triterpenoids,phenylpropanoids.A total of 297 compounds were identified by GC-MS,mainly including primary metabolites and volatile chemical components,such as organic acids,amino acids,saccharides,heterocycles,alcohols.The PCA analysis demonstrated that the metabolites of the four flowering periods were divided into two groups:bud,initial bloom and blooming periods clustered into one group,while wilting period clustered into the other group,the main differences were filtered and identified as flavonoids and triterpenoids,organic acids,respectively.Compared to the upright type,the flowers of vine type contained more characteristic flavonoids as differential metabolites during the bud,initial bloom and blooming periods,and some flavonoids decrease gradually with the development of flowering.Conclusion The results indicated that the flowers of C.speciosa possessed abundant active flavonoid metabolites for further utilization,and the best harvest stage is initial bloom,the best harvest plant is vine type.This study provides a scientific basis for the scientific development and rational use of the flowers of C.speciosa.