Abstract:Systematic research on the aroma metabolism of ''Xiangshui'' lemon throughout fruit development and their optimal harvest period remains limited. Therefore, this study employed ''Xiangshui'' lemons at different developmental stages as experimental materials to explore the dynamic variations of volatile components in fruit peel during maturation, elucidate the growth and developmental characteristics of ''Xiangshui'' lemon fruits, and determine the optimal harvest time, solvent extraction combined with gas chromatography–mass spectrometry (GC-MS) was employed to analyze the composition and content of volatile compounds in the fruit peel.The results revealed that single fruit weight presented an upward trend. Fruit longitudinal and transverse diameter growth tended to stabilize at 70 DAF. Juice yield, total soluble solids (TSS) and titratable acid (TA) contents increased gradually with fruit development, whereas vitamin C (Vc) content decreased continuously. The fruit started to turn yellow at 110 DAF.A total of 64 volatile components were identified in the fruit peel, among which monoterpenes and monoterpene aldehydes were the dominant substances, accounting for 80.96%~86.79% and 8.06%~14.54% of the total volatile components, respectively. D-limonene and citronellal were the core components. Their contents reached peak values of 51,422.15 µg?g-1 and 5,598.62 µg?g-1, respectively, at 110 DAF. Based on OPLSDA analysis, 10 differential characteristic volatile compounds were screened out. Linalool and dihydrocaryophyllene were the main accumulated components at the early developmental stage; nerol and citral were enriched at the middle stage. At 110 DAF, Dlimonene and βbisabolene accumulated substantially, which constituted a critical node for the formation of the unique sweet and mellow citrus aroma. In the late stage, the contents of key aromatic components decreased slightly.In conclusion, ''Xiangshui'' lemon exhibited the optimal aroma quality at 110 DAF. This study provides a scientific theoretical basis for determining the optimal harvest time in practical production.