Abstract: Objective:To explore the promotion of konjac glucomannan(KGM)and oligo-konjacglucomannan(OKGM)on lactose metabolism through in vitro fermentation to propose a convenient and innovative way of solving lactose intolerance. Methods:Different doses of KGM and OKGM were added into the milk powder to set up 6 experimental groups with high,medium and low doses. Meanwhile,negative control group(excluding KGM or OKGM)and positive control group(replacing KGM and OKGM with lactic acid bacteria)were set up. Under sterile conditions,the contents of the cecum and ileum of the mice were taken and subjected to anaerobic fermentation in vitro for 24 h,and the number of colonies,pH value,lactose content and lactase activity in different periods of fermentation were determined. Results:Compared with the negative control group,the number of lactic acid bacteria in ileum fermentation broth was significantly increased in medium and high dose group of KGM and low,high dose group of OKGM(P<0.05),and in cecum fermentation broth,the number of lactic acid bacteria in every KGM and OKGM test group was significantly increased(P<0.05). Lactase activity in ileum fermentation broth of the KGM high-dose group and OKGM high-dose group were significantly higher than that of the negative group(P<0.05),while lactase activity in cecum fermentation broth of the OKGM high-dose group was significantly higher than its negative group(P<0.05). According to the results of lactose content,in the ileum fermentation broth,compared with the negative group,4 h lactose content of KGM low dose group and OKGM each dose group decreased significantly(P<0.05),and the eventual lactose content of KGM medium and high dose group and OKGM each dose group were significantly lower(P<0.05)after 24 h fermentation. Similarly,lactose content of each test group in cecum fermentation broth were significantly lower than the negative group(P<0.05),and it was noticeably that the results of KGM medium and OKGM medium and high dose group were also higher than its positive group(P<0.05). And 24 h lactose content of KGM low and middle dose group and OKGM medium and high dose group were also significantly lower(P<0.05). Conclusion:Milk powder added with KGM or OKGM can promote the growth of probiotics such as Lactobacillus in the intestinal tract. By enhancing the activity of lactase in the cecum and ileum,the content of lactose in milk powder can be significantly reduced(There is a significant effect after 4 h during fermentation),thus promoting the metabolism of lactose.