Abstract: 【Objective】 To reveal the differences in endogenous hormone contents between completely sterile flowers and fertile flowers，and to screen the key endogenous hormones involved in the formation of sterile phenotypes in completely sterile flowers，which could provide an important reference for the study of the mechanism of failure of completely sterile flowers. 【Method】 The fertile tea plant Foxiang 2（female parent）and Fudingdabaicha（male parent），as well as the completely sterile tea plant Yunchayirui（F₁ hybrid），were analyzed for 22 endogenous hormones and related metabolites in both flower buds and fully bloomed flowers using high performance liquid chromatography-electrospray ionization tandem mass spectrometry. Correlation analysis of endogenous hormones and related metabolites was performed，along with principal component analysis and cluster analysis among different varieties. 【Result】 Compared to fertile flowers，Yunchayirui had higher contents of L-tryptophan（Trp），tryptamine（TAM），indole-3-acetic acid（IAA）， IAA-aspartic acid（IAA-Asp）and zeatin（ZT），and lower contents of indole-3-acetamide（IAM），isopentenyladenine （IP）and isopentenyl adenosine（IPA）at different flowering stages. The overall trends of trans-zeatin（TZ），trans-zeatin riboside （TZR） and dihydrozeatin riboside （DZR） were consistent，with their contents being significantly higher in flower buds than in fully bloomed flowers in both parents（P<0.01，the same below），while it was the opposite was observed in Yuncha. The contents of gibberellins A₄（GA₄）and gibberellins A₇（GA₇）in Yuncha were consistently extremely significantly higher than in parents，while abscisic acid（ABA）content was extremely significantly lower than in parental lines. Jasmonic acid（JA）content was extremely significantly higher in Yuncha fully bloomed flowers than in buds，in contrast to the parents，and jasmonoyl-isoleucine（JA-Ile）content was extremely significant lower than the parents at the same time，both in buds and in fully bloomed flowers. The results of the correlation analysis showed that there were more complex positive or negative correlations between different endogenous hormones in terms of content. The distribution patterns of endogenous hormones in Yunchayirui flowers differed markedly from those of the parents，and the flower buds and fully bloomed flowers of Yunchayirui clustered together，indicating more similar endogenous hormone levels. 【Conclusion】 The surpluses and deficits of multiple endogenous hormones，as well as their interactions，are jointly involved in the formation of the completely sterile phenotype of Yunchayirui. Moreover，the higher contents of IAA-Asp，ZT，GA₄ and GA₇，and the lower contents of ABA，IP and IPA in Yunchayirui may be closely related to its completely sterile phenotype.