Abstract: In order to explore the changes of quality and volatile flavor substances of Liupao old leaves tea. In this study, ‘Cangwu tea population variety(QY)’ and ‘Wantian tea population variety(WT)’ were used to make Liupao old leaves tea with different parts (green stem leaves, green and red stem leaves, red stem leaves, lateral branches leaves and old leaves), through sensory evaluation, biochemical composition analysis, and headspace solid-phase microextraction-gas chromatography-mass spectrometry technology (HS-SPME-GC-MS), combined with odor activity value (OAV) and orthogonal partial least squares discrimination analysis (OPLS-DA) method, the changes of its volatile flavor substances were analyzed. The sensory evaluation results indicated that both tea samples of the two varieties exhibites common characteristics of woody fragrance, fresh aroma, and rich and mellow taste, with relatively low bitterness and astringency. The biochemical analysis revealede that the water extract content, tea polyphenols content, free amino acids content, soluble sugar content, caffeine content, gallic acid content, total catechins content, phenol-amine ratio, and sugar-caffeine ratio ranged from 25.92% to 37.60%, 8.80% to 13.74%, 2.61% to 2.88%, 8.33% to 16.81%, 0.5498% to 1.82%, 2.73% to 9.05%, 3.47% to 8.409%, 3.26 to 4.97, and 6.58 to 18.27, respectively. As the tenderness of fresh leaves decreases, the total content of tea polyphenols and catechins in WT and QY tea samples shows a decreasing trend, while the content of gallic acid shows an increasing trend. A total of 82 volatile components were identified, including 2 other compounds, 3 hetero-oxides, 3 terpenoid compounds, 5 acid compounds, 7 esters compounds, 8 alcoho compounds, 24 aldehyde compounds, and 30 ketone compounds.Amond them, the content of aldehydes accounted for 29.27%, and that ketones accounted for 36.59%. The OPLS-DA model was established to effectively distinguish the two varieties of Liupao old leaveas tea. Further screening of aroma components with OAV>1 was conducted, among which 2-Buten-1-one,1-(2,6,6-trimethyl-1,3-cyclohexadien-1-yl)-,(E)-(flowery aroma), 5,9-Undecadien-2-one, 6,10-dimethyl- (clean aroma, flowery aroma and honey aroma) are important aroma components of Liupao old leaves tea. Compounds such as 2-Undecanone, 6,10-dimethyl-(milky aroma, flowery aroma and lemony aroma), 3-Buten-2-one,4-(2,2,6-trimethyl-7-oxabicyclo4.1.0hept-1-yl)-(sweet aroma, floral aroma), and 2(3H)-Furanone,dihydro-5-pentyl-(coconut aroma) are considered as characteristic aroma components of WT. Compounds such as isophorone(minty aroma), (E,E)-2,4-hexadienal(flowery aroma ,fruity aroma) and 2,4-Octadienal,(E,E)-(honey and rosy aroma) are considered as characteristic aroma components of QY. In conclusion, both QY and WT types of Liupao old leaves tea possess the characteristics of rich and mellow taste, low bitterness and astringency, and abundant internal substances. This research provides a scientific basis for the quality evaluation and raw material selection of Liupao old leaves tea.