Abstract: Chrysanthemum morifolium Ramat. is a medicinal and edible dual-purpose herb that is highly beneficial to health, possessing a variety of pharmacological effects and being widely used in numerous applications. However, the high moisture content and perishable nature of fresh chrysanthemum make its preservation challenging, necessitating processing. The drying process can effectively extend the shelf life by reducing microbial growth through dehydration, and different drying methods have significant impacts on the quality characteristics and flavor profiles of chrysanthemum. In this study, three drying methods were employed to dehydrate chrysanthemum, namely hot air drying (HD), infrared combined hot air drying (IHD), and vacuum drying (VD), and their effects on drying characteristics, color, nutritional quality, microstructure, and flavor components were systematically analyzed. Results showed that IHD exhibited the shortest drying time (7.3 h), followed by HD (8.8 h) and VD (18.6 h). The Page and Weibull models best described the drying behavior (R² > 0.997), and the drying constant a in the Page model was highest for IHD (0.5722) and lowest for VD (0.1661), further confirming the fastest moisture diffusion in IHD. IHD and HD yielded significantly higher L* and b* values than VD (p < 0.05), indicating better color retention. Microstructural observation revealed that VD best preserved cellular integrity with honeycomb-like structures, followed by IHD with moderate porosity, while HD showed severe structural shrinkage. IHD achieved the highest soluble sugar content (42.27 ± 2.04 mg/g), 19.34% and 88.54% higher than HD and VD respectively, attributed to shorter drying time minimizing Maillard consumption. Total phenolic and flavonoid contents followed the order IHD > HD > VD (p < 0.05). HPLC analysis revealed different stability patterns: chlorogenic acid, luteoloside, and isochlorogenic acid were highest in IHD, while luteolin and apigenin were highest in VD due to prolonged β-glucosidase activation under longer drying duration. The total content of six characteristic bioactive compounds (chlorogenic acid, luteoloside, isochlorogenic acid, apigenin, luteolin, and buddleoside) maintained the trend IHD > HD > VD. E-nose PCA effectively discriminated the three drying groups with 91.3% cumulative contribution (PC1 = 60.1%, PC2 = 31.2%). GC-IMS identified 68 volatile compounds across all samples, with hierarchical clustering revealing five characteristic regions showing distinct compound distributions among drying methods. For instance, IHD exhibited the highest abundance of floral and fruity compounds such as pentanal and β-myrcene, while VD showed the highest levels of acetoin and 2-formyl-5-methylthiophene, and HD presented high levels of terpenes such as α-pinene. GC-MS identified 208 volatile compounds. HD, IHD, and VD contained 172, 183, and 179 compounds respectively, with 105 common compounds forming the core volatile profile. Total volatile concentration was highest in IHD (421.11 mg/kg), significantly exceeding HD (355.88 mg/kg) and VD (397.24 mg/kg). Terpenes (87 compounds) and alcohols (49 compounds) dominated all samples. PLS-DA identified 20 key differential volatile markers (VIP > 1), primarily terpenes and alcohols including 3,4,4-trimethyl-2-cyclohexen-1-one, α-farnesene, β-myrcene , β-vetivenene and so on. Most VIP markers were common compounds, indicating drying methods modulated abundance rather than generating unique compounds. Characteristic flavor profiles emerged: HD featured herbal, cooling, and woody notes (high eucalyptol, camphene); IHD exhibited roasted, spicy, and caramel-like aromas (elevated furans, esters, phenolics) from Maillard reactions; VD delivered fruity, sweet, and floral notes (high terpenes) closest to fresh chrysanthemum. Alcohols correlated with floral/fruity notes, while terpenes contributed herbal/green characteristics, consistent with E-nose observations. In conclusion, IHD emerges as the optimal processing technology, offering superior drying efficiency, better retention of nutritional components and most bioactive compounds, and the highest total volatile concentration with desirable roasted and spicy notes, through synergistic infrared and hot air heating that accelerates drying and promotes compound release. These findings provide a scientific basis for optimizing industrial chrysanthemum drying processes to achieve desired quality attributes for high-value products. Future studies should investigate the interactive effects of temperature and drying methods, as well as the potential of infrared-combined vacuum drying strategies.