Abstract： Objective： To observe the effect of Jianpi Sanjing method on blood glucose control， intestinal flora and immune function in patients with type 2 diabetes mellitus. Methods：A total of 118 patients with type 2 diabetes mellitus were selected and divided into the control group and the observation group according to the random number table method，with 59 cases in each group. The control group was treated with oral administration of metformin hydrochloride tablets， the observation group was additionally treated with Jianpi Sanjing tang based on the treatment of the control group， and both groups were continuously treated for three months. The total clinical effects and the changes of Chinese medicine syndrome scores， blood glucose indexes， including fasting blood glucose(FBG)， postprandial two- hour blood glucose(P2hBG) and glycosylated hemoglobin(HbA1c)，intestinal flora and immune factors，including CD3 +，CD4 + and CD4 +/CD8 +，before and after treatment were compared between the two groups. Results：The clinical effective rate was 83.05% in the observation group， significantly higher than that of 64.41% in the control group(P＜0.05). After treatment， the Chinese medicine syndrome score， the levels of FBG， P2hBG and HbA1c in the observation group were significantly decreased when compared with those in the control group(P＜0.05)； after treatment， the intestinal yeast， enterobacteriaceae and enterococcus in the observation group were significantly decreased when compared with those in the control group(P＜0.05)， and the intestinal bifidobacterium， lactobacillus and clostridium butyricum in the observation group were significantly increased(P＜0.05)；after treatment，the levels of CD3+，CD4+ and CD4+/CD8+，in the observation group were significantly increased when compared with those in the control group(P＜0.05). Conclusion： Jianpi Sanjing method has a remarkable curative effect on patients with type 2 diabetes mellitus，which can effectively alleviate the clinical symptoms，reduce the insulin resistance，regulate the balance of intestinal flora and improve the immunity.