Abstract: In order to explore the composition of main volatile compounds and the difference of aroma compounds in Sauce-flavor Baijiu with different sweet flavor characteristics, sensory evaluation method was used to select Sauce-flavor Baijiu samples, the volatile components were analyzed by headspace solid phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS), and partial least squares discriminant analysis (PLS-DA) was used to analyze different Baijiu samples and their flavor differences substances. The results showed that the samples were divided into three groups, and the intensity values of sweet-flavor in each group were 4.0~5.0, 3.0~4.0 and 0.0~3.0, respectively, and a total of 68 volatile flavor compounds were characterized, including 27 esters, 12 alcohols, 10 aldehydes and ketones, 3 acids, 10 aromatics and 6 terpenes, among them, esters, aromatics and alcohols with sweet and fruity aromas were the three most abundant types of compounds in different Baijiu samples, and the content was the highest in Baijiu samples with a sweet flavor intensity greater than 3.0, indicating that these three types of substances had an important impact on the flavor characteristics of sweet aroma. There were 25 potential difference compounds affecting the three groups of Baijiu samples, and the related sweet flavor markers were mainly 3-methyl butanol, ethyl octanoate, isobutyl lactate and ethyl phenylacetate, indicating that these substances were the important aroma compounds that cause differences between different sauce-flavor Baijiu samples with different sweet flavor characteristics.