Abstract: To investigate the effects of field-grown flue-cured tobacco maturity on mechanical harvesting performance, middle (C) and upper (B) leaves of Zhongyan 100 were selected as experimental materials. Three maturity levels—low (M1), medium (M2), and high (M3)—were tested, and the following parameters were measured: mechanical harvesting quality, mechanical property indices, stem-leaf angles, and cell wallrelated components. A correlation analysis was conducted between cell wall components and mechanical properties. The results showed that: With increasing maturity, 1) The mechanical harvesting damage rate first decreased and then increased. The damage rates of CM2 and BM2 were 6.96% and 8.42%, respectively, with significant differences between treatments. The harvesting completeness rate gradually increased, but no significant difference was observed between medium and high maturity levels. 2) The maximum tensile force of mesophyll and veins decreased, while the displacement at maximum tensile force increased. The flexibility coefficient and elongation rate increased, whereas the elastic modulus decreased. The bending strength of veins showed a declining trend. 3) Cellulose, hemicellulose, and lignin contents exhibited a gradient decline (CM1 > CM2 > CM3, BM1 > BM2 > BM3) and were significantly positively correlated with elastic modulus and bending strength. 4) The stem-leaf angles of middle and upper leaves increased, while the stem-leaf binding force gradually decreased. The stem-leaf angles of CM3 and BM3 were 67.78°-87.60° and 69.45°-86.89°, respectively, which were deemed unfavorable for mechanical harvesting operations. Therefore, it is recommended to perform mechanical harvesting when the field-grown tobacco leaves reach medium maturity to achieve collaborative optimization of net extraction rate and damage rate.