Objective To investigate the aroma changes of sauce-flavored Baijiu during different aging periods, and to provide a theoretical basis for Baijiu aroma analysis and modern processing technology research.Methods Electronic nose, gas chromatography-mass spectrometry (GC-MS), and gas chromatography-ion mobility spectrometry (GC-IMS) were employed. Sauce-flavored Baijiu with different aging times (original liquor, 1-year aged, and 5-year aged) was used as the research objects. Combined with multivariate statistical methods, including principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA), the differences in volatile flavor compounds of Baijiu with different aging times were analyzed.Results A total of 1 626 volatile compounds were detected in the three Baijiu samples. Based on the calculation of relative odor activity value (r_OAV) and screening of compounds with r_OAV≥1, 47 important volatile compounds were identified, including 1 amine, 6 alcohols, 2 aromatic hydrocarbons, 1 phenol, 1 halogenated hydrocarbon, 3 ethers, 10 aldehydes, 3 terpenoids, 5 ketones, 3 heterocyclic compounds, and 12 esters.Conclusion The aroma characteristics of Baijiu with different aging times are similar, but clear differences also exist. With increasing aging time, the contents of higher alcohols, aldehydes, and esters-contributing to a rich and delicate flavor-increase, while pungent and irritating substances decrease. As a result, the aroma of Baijiu becomes more stable and mellow, with a more complex aroma profile.