Abstract: This study investigated the effects of α-amylase enzymatic hydrolysis, lactic acid bacteria fermentation, and combined enzymatic-fermentation treatments on the nutritional quality, antioxidant activity, bioaccessibility of total phenolics and flavonoids, and volatile flavor compounds of chestnut milk. The results demonstrated that both fermentation and enzymatic-fermentation treatments significantly increased the content of total phenolics and flavonoids in chestnut milk (P<0.05) compared to the control. Enzymatic-fermentation treatment exhibited the highest antioxidant activity, with significant improvements in hydroxyl radical, ABTS⁺ radical, and DPPH radical scavenging capacities by 15.80%, 14.84% and 29.29%, respectively. Additionally, enzymatic-fermentation significantly enhanced the bioaccessibility of total phenolics and flavonoids in both gastric and intestinal stages, with increases of 45.81% and 78.95% for phenolics, and 59.43% and 91.17% for flavonoids, respectively. The enzymatic-fermentation treatment also had the most profound effect on the volatile flavor compounds in chestnut milk. This combined approach resulted in the detection of 35 different aroma compounds, primarily including 2,3-butanedione, 1,2-butanediol and acetaldehyde, contributing to a creamy and fruity aroma profile. In conclusion, the combination of enzymatic hydrolysis and fermentation effectively improved the nutritional components and flavor characteristics of chestnut milk, enhancing its nutritional value and antioxidant capacity.