Abstract: Objective:We elucidated the dynamic evolution of volatile flavor compounds during the fermentation of sufu. Methods:The physicochemical properties and volatile components of sufu at fermentation stages of 0, 3, 6, 9, 12, and 15 days were systematically analyzed using gas chromatography–mass spectrometry (GC–MS), electronic nose technology, and principal component analysis (PCA). Results: During days 0~3, the main flavor compounds in sufu were aldehydes, with total relative contents ranging from44.9% to 58.3%. Among these, hexanal accounted for 10.2% to 15.8%, and 2-hexenal for 7.5% to 12.3%, collectively imparting green note and fruity notes. By the 15 d, the alcohol substance 1-hexanol increased from 5.2% to 13.6%, while the esters ethyl acetate and ethyl butyrate rose from 1.8% to 11.5% and from 0.9% to 7.3%, respectively (P<0.01), indicating significant accumulation. The total ester content increased by 5.4 times, establishing a fruity aroma foundation. By the 15 d, ethyl acetate reached 13.8%, acetic acid increased from 12.5% to 33.5%, and the sulfur compound dimethyl sulfide increased from 0.3% to 2.8%. The pH value decreased continuously from 6.5 to 4.0.In the early storage period, aldehydes dominated with green note and fruity characteristics; in the mid-term, alcohols and esters accumulated significantly, forming a fruity base; in the later stage, esters, carboxylic acids, and sulfur compounds interacted synergistically, reaching peak flavor complexity. Meanwhile, the pH continued to decrease over time, indicating gradual accumulation of acidic compounds. Electronic nose analysis showed that the response value of alcohol/aldehyde sensors increased from 40 to 120, while the sulfide response reached 120 by day 15, with a 3.2-fold increase in sulfide formation rate. PCA revealed that PC1 accounted for 98.98% of the variance, effectively distinguishing different fermentation stages. Key differentiating factors included sulfide (W2W loading > 0.45) and esters (W5C loading > 0.40), reflecting changes in flavor compounds across fermentation stages.This study quantified the stage-specific variations in sufuflavor formation, clarified the patterns of flavor development, and provided data support for process optimization.