Abstract: The incorporation of passion fruit juice into fresh summer-harvested Yunkang No.10 tea leaves, at both pre- and post-fermentation stages, yielded Congou black tea. A sensory evaluation, physicochemical composition, and headspace solid phase micro extraction and gas chromatography mass spectroscopy (HS-SPME-GC-MS) were conducted to investigate the effect of adding passion fruit juice before and after fermentation on the quality of Congou black tea, with the objective of improving the utilisation rate of summer tea. The results demonstrated that the appearance score of black tea with added passion fruit juice, both prior to and following fermentation, was higher than that of traditional black tea. The tea soup exhibited a redder and brighter hue than that of traditional black tea, and the black tea with added passion fruit juice prior to fermentation (BTR) displayed a rich aroma with a greater diversity of aromatic compounds. The addition of passion fruit juice before and after fermentation resulted in an increase in the content of soluble sugars, tea polyphenols, amino acids, caffeine, and theaflavins in black tea (P<0.05), while reducing the content of thearubigins and theaflavins (P<0.05). Aroma analysis demonstrated the existence of a total of 72 volatile organic compounds (VOCs), with alcohols, heterocyclic compounds, and esters representing the most prevalent VOCs. The key VOCs responsible for the floral and fruity aromas observed in black tea with added passion fruit juice before and after fermentation were identified as geraniol, linalool, benzaldehyde, phenylacetaldehyde, nonanal, α-ionone, β-lonone, and methyl salicylate. 2-Heptanol and β-damascenone were identified as characteristic VOCs of passion fruit juice and black tea added before and after fermentation, respectively. β-cyclocitral, myrcene, and linalyl acetate were identified as unique to BTR. Jasmone was identified as a distinctive VOC of black tea with the addition of passion fruit juice following the fermentation process (BTF). In conclusion, and the addition of passion fruit juice before and after the fermentation process has been demonstrated to enhance the flavour profile of summer black tea. The incorporation of passion fruit juice subsequent to the fermentation process was observed to exert a more pronounced effect.