As a premium cultivar widely applied in black tea processing, Meizhan tea exhibits great adaptability for manufacturing high-quality black tea, and the tenderness of fresh leaf raw materials serves as a pivotal regulatory factor governing the sensory quality and flavor formation of finished black tea. In the present study, fresh tea shoots with four maturity grades, including single bud (DY), one bud and one leaf (YY), one bud and two leaves (EY), as well as one bud and three leaves (SY), were collected from Meizhan tea plants to produce congou black tea, and systematic comparative analyses were conducted to investigate the discrepancies in sensory characteristics, biochemical compositions and volatile aroma profiles among tea samples derived from different tender raw materials. Sensory evaluation results demonstrated that the comprehensive sensory quality of Meizhan congou black tea gradually declined with the decrease of fresh leaf tenderness, and the tea products processed from high-tenderness fresh leaves possessed prominent floral aroma, distinct fresh taste and sweet mouthfeel. Significant differences (P < 0.05) were observed in the biochemical components of the four black tea samples, wherein the contents of water-soluble extracts, tea polyphenols, amino acids and caffeine were positively correlated with fresh leaf tenderness, while flavonoids presented an opposite accumulation trend with the increase of leaf maturity; the accumulation levels of thearubigins (TRs) and theabrownins (TBs) increased continuously as fresh leaves matured, whereas theaflavins (TFs) were predominantly enriched in high-tenderness samples (DY and YY). A total of 190 volatile aroma compounds were identified in all tea samples, and principal component analysis (PCA) combined with orthogonal partial least squares-discriminant analysis (OPLS-DA) based on the relative content of volatile components achieved effective classification and differentiation of the four sample groups. Twelve differential core aroma-active compounds were screened out following the comprehensive screening criteria of variable importance in projection (VIP) ≥ 1, P < 0.05 and odor activity value (OAV) > 1. Among these characteristic volatiles, geraniol, δ-cadinene and cis-3-hexenyl benzoate decreased consistently with the reduction of leaf tenderness, while trans-2-hexenol, n-hexanol, (Z)-3-hexenyl hexanoate, γ-nonalactone, 1-octanol and trans-3-hexenol displayed an opposite accumulation tendency. The nine screened differential aroma compounds can be regarded as critical chemical markers for distinguishing flavor variations of Meizhan black tea processed from fresh leaves with different tenderness, which provides a reliable chemical basis for the rapid identification and quality evaluation of Meizhan black tea with different raw leaf maturity.