Abstract: Using prunes as the raw material, Chinese prune Jiaosu was prepared by co-inoculating yeast and lactic acid bacteria for fermentation. This study investigated the dynamic changes in physicochemical properties and antioxidant capacity of Chinese prune Jiaosu during fermentation. Gas chromatography-ion mobility spectrometry (GC-IMS) combined with principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) was employed to characterize the volatile compounds across different fermentation stages. Results demonstrated that: Fermentation significantly altered the biochemical profile, with total acid, total phenols, and total flavonoids increasing by 63.22%, 24.74%, and 44.12%, respectively. Concurrently, pH, soluble solids, and reducing sugars decreased by 14.29%, 18.94%, and 28.54%, respectively. Antioxidant activities, as measured by DPPH and ABTS⁺ radical scavenging capacities, enhanced by 310.47% and 143.43%, respectively. A total of 37 volatile compounds were identified across four fermentation stages, including 14 esters, 8 alcohols, 7 aldehydes, 4 terpenes, 3 ketones, and 1 amine. Multivariate statistical analyses revealed distinct flavor profiles at different stages, with key discriminative compounds including ethanol, hexanol (D), ethyl formate, 2-pentanone, hexanol (P), butylamine, ethyl acetate, octanal, isoamyl alcohol, methyl acetate, propanol, isopropanol, ethyl butanoate (M), and ethyl propanoate. This research confirmed that fermentation improved the total polyphenol, total flavonoid contents and antioxidant activities, enhanced the flavor profile by increasing the types and content of volatile compounds, enriching the characteristic aroma and pleasant flavor of the Chinese prune Jiaosu.