Abstract:In order to extract chitin from shrimp shell and investigate it's hypoglycemic effect， response surface method and desirability function were applied to optimism the extraction process of chitin from shrimp shell. Then the hypoglycemic effect of chitin was studied. The diabetic mice model was established by using alloxan. After one month's treatment，the hepoglycemic effects of chitin，metformin and chitin combined with metformin on the body weight，blood glucose and so on were studied. The optimum extraction condition of chitin was as follow：pH 11，EDTA concentration 11 %，reaction time 2 h，solid-liquid ratio 1 ∶ 14 （g/mL），after filtration，drying，hydrogen peroxide bleaching and drying，vested chitin extract. Compared verification tests with the model predictive value，the relative error was 2.8 % which was improved by 20.3 %. The hypoglycemic results showed that，compared with the model group，or the chitin and metformin alone，the combination of the two drugs could relieve the weight loss of mice induced by diabetes mellitus （P<0.05），and the serum total cholesterol，triglyceride，blood glucose levels were significantly reduced （P<0.01，P<0.01，P<0.01，P<0.01）. The insulin expression increased （P<0.05）. The mouse organ index showed that the combined administration of chitin and metformin could also relieve the damage to the pancreas tissue （P<0.05）. Chitin can enhance the efficacy of metformin in lowering blood glucose and blood lipid，and it has important significance in clinical application.