Abstract: To promote the high-value utilization of Huangshui, a byproduct of Baijiu brewing, Huangshui was used as the raw material, and the yield of crude Huangshui polysaccharide (cHSP) was used as the evaluation index. The isolation process of cHSP was optimized using single-factor experiments combined with response surface methods. Subsequently, enzymatic deproteinization was employed to prepare Huangshui polysaccharide (HSP), followed by in vitro evaluation of antioxidant and hypoglycemic activities. Furthermore, the inhibition mechanism of HSP on α-amylase was analyzed using enzyme kinetics. The results showed that the optimal ethanol precipitation conditions for cHSP were as follows: temperature of 5.8 ℃, time of 14.3 h, and ethanol volume ratio of 1:5. Under these conditions, the cHSP was 7.36±0.03 mg/mL. Activity studies in vitro indicated that HSP exhibited strong scavenging capacity against ABTS⁺, DPPH, and hydroxyl radicals, with IC₅₀ values of 3.38, 1.53, and 3.36 mg/mL, respectively. Meanwhile, the IC₅₀ values of HSP against α-glucosidase, pancreatic amylase, and α-amylase were 3.75, 2.40, and 2.08 mg/mL, respectively, indicating a potential hypoglycemic effect. Enzyme kinetic analysis showed that the inhibitory effect of HSP on α-amylase was mixed. The inhibition constant (K_I) was 4.21 mg/mL, which was lower than the inhibition constant for the enzyme-substrate complex (K_IS=8.62 mg/mL). This suggests that HSP has a stronger affinity for free α-amylase. The findings indicate that Huangshui polysaccharide have certain antioxidant activity and excellent α-amylase inhibitory capacity, highlighting their potential applications in the development of natural antioxidants and functional foods for hypoglycemia.