Abstract: To investigate the effects of exogenous enzymes on the quality of Toona sinensis fermented tea, this study evaluated the sensory attributes, active components, antioxidant activity, and volatile flavor compounds following treatment with cellulase (CE), flavourzyme (FLA), and polyphenol oxidase (PPO) during fermentation process. Compared with the control group (CK), the CE, FLA, and PPO groups with exogenous enzymes addition showed significantly higher sensory scores, active components content, DPPH· scavenging capacity, and total reducing ability. The CE group exhibited the highest sensory scores and significantly elevated the contents of free amino acids, tea polyphenols, total flavonoids, theaflavins, and thearubigins increasing by 12.44%, 8.13%, 9.25%, 12.50%, and 9.76% compared with the CK group, respectively. The majority of active components in the FLA group were lower than those in the CE group or PPO group. Notably, the PPO group exhibited a bright red tea liquor and a bright bottom in the leaves, with the highest contents of water extract (42.63 g/100 g), soluble sugar (5.27 g/100 g), and theabrownins (15.15 g/100 g). Both the CE and PPO groups demonstrated strong scavenging capacities for DPPH· and ·OH, while the FLA group exhibited the highest total reducing ability. Gas chromatography-mass spectrometry identified 74 volatile compounds across five chemical classes, with 43 common components accounting for more than 84% of the total relative content in each group. Compared with the CK group, the CE, FLA, and PPO groups detected more aldehydes, alcohols, and esters. Among these, the PPO group demonstrated the highest variety and relative content of volatile flavor compounds. Based on odor activity value (OAV) and orthogonal partial least squares-discriminant analysis (OPLS-DA), 15 key volatile flavor compounds (OAV>1) and 17 differential volatile flavor compounds (variable importance in projection, VIP>1) were identified, respectively. Among these, 6 compounds, namely phenylacetaldehyde, p-methyl benzaldehyde, β-caryophyllene, α-caryophyllene, eugenol and (E)-β-lonone, were defined as key differential volatile flavor compounds with both OAV>1 and VIP>1. In conclusion, the PPO group exhibited the best overall quality, characterized by a mellow and fresh tea liquor, bright red color, high level of active components, strong antioxidant activity and a rich characteristic flavor profile.