Abstract: OBJECTIVE To evaluate the effect of saxagliptin on the regulation of blood glucose fluctuations in patients with type 2 diabetes mellitus. METHODS One hundred forty-five patients were randomly divided into 3 groups, saxagliptin low-dose(SG-L) group, saxagliptin high-dose(SG-H) group, and metformin(MG) group, gave metformin 1 500 mg + saxagliptin 2.5 mg, metformin 1 500 mg + saxagliptin 5 mg, and metformin(1 500-2 000 mg), respectively. The glucose level, dynamic glucose and pancreas islet function were measured. RESULTS After treatment, compared with the MG group, the blood glucose of the SG-H group was significantly reduced 2 h after breakfast, before lunch, 2 h after lunch, and before dinner, 2 h after dinner and 4 h after dinner(P < 0.05); mean blood glucose fluctuation range, standard deviation of blood glucose level, maximum blood glucose fluctuation range, the mean blood glucose level value was significantly reduced(P < 0.05); HOMA-β levels was significantly increased, HOMA-IR and fasting insulin levels were reduced significant(P < 0.05). CONCLUSION Saxagliptin combined with metformin can effectively control glucose in patients at different time points, reduce glucose fluctuation, while improving insulin β-cell function, improving insulin resistance in patients with type 2 diabetes mellitus.