Objective To investigate the effect of Intensive Insulin therapy combined with Sodium-glucose Transporter 2 Inhibitor on blood glucose fluctuation in patients with brittle diabetes. Methods A total of 82 cases of brittle diabetes admitted to Dalian Fifth People′s Hospital were selected retrospectively from January 2018 to October 2020. They were divided into control group and observation group according to random number table method, with 41 cases in each group. The control group was treated with Intensive Insulin therapy, while the observation group was treated with Intensive Insulin therapy combined with Sodium-glucose Transporter 2 Inhibitor. The plasma glucose and blood glycemic variations, insulin dosage, glycosylated hemoglobin (HbA1c) and hypoglycemia events were compared between the two groups before and after treatment. Results After treatment, the standard deviation of intra day blood glucose, the large amplitude glycemic excursions, the postprandial glycemic excursions, the insulin dosage and HbA1c of observation group were lower than those of control group, the incidence of hypoglycemic events and severe hypoglycemia of observation group were lower than those of control group, the differences were statistically significant (P＜0.05). Conclusion Combination of Sodium-glucose Transporter 2 Inhibitor and Intensive Insulin therapy can significantly improve glucose metabolism in brittle diabetes, and reduce insulin dosage and hypoglycemic events.