Abstract: Aroma is a key factor in evaluating tea quality. To investigate the dynamic evolution of aroma compounds during the processing of Guangnan Dixu black tea, this study utilized headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS), to systematically analyze changes in volatile compounds at five processing stages: fresh leaves (XY), withering (WD), rolling (RN), fermentation (FJ), and dried tea (GC). Aroma-active values (OAV) and principal component analysis (PCA) were used to identify key aroma compounds at each processing stage. A total of 96 volatile compounds were identified, including alcohols, aldehydes, esters, ketones, alkanes, olefins, and others. The aroma components showed significant dynamic changes during processing. At the withering (WD) stage, the content of alcohols (such as linalool) decreased, while some aldehydes began to form. During the rolling (RN) stage, the total amount of volatile compounds increased the most. Aldehydes (such as (E)-2-hexenal), ketones (such as β-ionone), and some alkenes increased significantly. In the fermentation (FJ) stage, aldehydes (such as nonanal) and some esters (such as methyl salicylate) continued to increase in concentration. However, during the drying stage, the total amount of esters sharply decreased due to high-temperature volatilization. At the dried tea (GC) stage, certain alcohol oxides (such as (E)-linalool oxide (pyran)) and aldehydes (such as (Z)-3-nonen-1-ol) reached their peak concentrations. Principal component analysis (PCA) showed that samples from the rolling stage were clearly separated from those of other stages, indicating that rolling was a critical process for aroma formation in Guangnan Dixu black tea. In the final dried tea samples, nine key aroma compounds with OAV greater than 10 were identified: 2-methylbutanal, heptanal, phenylacetaldehyde, trans-linalool oxide (furan type), nonanal, linalool, (Z)-3-nonen-1-ol, (E)-linalool oxide, and benzaldehyde. Among these, 2-methylbutanal, nonanal, linalool, (Z)-3-nonen-1-ol, and benzaldehyde (all with OAVs greater than 100) made particularly significant contributions. Together, they formed the characteristic aroma profile of Guangnan Dixu black tea, which featured intense floral, sweet, fruity, and fresh grassy notes.