Abstract: To investigate the characteristic flavor compounds and quality of ancient-tree green tea from Tongzi, Guizhou. This study analyzed 12 baked green-tea samples produced from individual arbor-type large-leaf ancient trees. Sensory evaluation, high-performance liquid chromatography (HPLC) and headspace solid-phase micro-extraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) were employed to determine sensory quality, key physicochemical components and volatile aroma compounds, followed by hierarchical clustering and correlation analyses for comprehensive assessment. Results showed that all teas scored above 90 points in sensory evaluation, exhibiting typical "floral aroma and fresh mellow taste". Key quality indices revealed high amino-acid contents (up to 5.27%), phenol-to-amino ratios of 5.68-8.58, total catechins at 9.14-15.68 %, and low ratios of galloylated catechins tonon-galloylated catechins (1.22-2.54). GC-MS identified 24 key aroma compounds, linalool, methyl salicylate, jasmonate, α-farnesene and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate were the core contributors to the dominant floral-fruity aroma. Cluster analysis divided the 12 samples into two groups: Group I (samples 6, 7, 8) featured high amino acids and a sweet-mellow profile, while Group II was characterized by intense floral and fruity aromas.In conclusion, Tongzi ancient-tree green tea possesses outstanding quality, and its unique flavor profile is closely linked to specific volatile aroma constituents and their concentrations. This study provides a scientific basis for quality evaluation, resource utilization and product positioning of Tongzi ancient-tree green tea.