Abstract: Taking the inhibition of α-amylase and α-glucosidase related to hypoglycemia as indicators,the inhibition effect of fermentation of purple potato products by anaerobic or aerobic fermentation with purple potato mud or purple potato juice as substrates was compared with that of single or mixed strains of Lactobacillus plantarum,Lactobacillus bulgaricus,Streptococcus thermophilus,Baker's yeast with low sugar,Saccharomyces cerevisiae(BV818) and Saccharomyces cerevisiae(RY1) respectively. The content changes of polysaccharides,polyphenols and flavones in the products were analyzed. The results showed that the fermentation improved the inhibition of α-amylase and α-glucosidase activity. Single bacteria was better than mixed bacteria fermentation products,and purple sweet potato juice was better than purple sweet potato mud fermentation products. Meanwhile,the contents of non-starch polysaccharide,total phenol and total ketone in fermented purple potato products were increased compared with those in unfermented purple potato products. The highest inhibition rate of hypoglycemic enzyme activity was found in the fermented purple potato products with the purple potato juice as the substrate and the low sugar Baker's yeast as the starter. The α-amylase activity inhibition rate was 63.5%,the α-glucosidase activity inhibition rate was 70.9%,the non-starch polysaccharide in the products was 3.52%,total phenol was 10.68 mg/10 g,total ketone was 0.78 mg/10 g.