Abstract: Objective To analyze the intervention effects of Insulin Detemir Injection (Det) and Isophane Protamine Biosynthetic Human Insulin Injection (NPH) on the level of blood glucose and basal islets in gestational diabetes mellitus.Methods Patients with gestational diabetes mellitus (n=80) who met the criterias of this study were divided into observation group and control group by random number table. Insulin was provided to the two groups. The observation group and the control group were also given Det and NPH, respectively. The blood glucose level and the time to reach the standard before and after treatment between the two groups were compared. The situation of insulin usage at the 7^th day, fasting insulin level (FINS), and pancreatic islet B-cell function before and after treatment between the two groups were also compared. The occurrence of hypoglycemia, body mass index (BMI) after treatment and the delivery outcomes were recorded.Results All of the time of blood glucose reaching the standard of the observation group was shorter than that of the control group. The fasting blood glucose (FBG) at the 7^th day and the level of 2 hours' postprandial blood glucose (2 hPG) before and after treatment in the observation group were lower than that in the control group. Although the dosage of Det in the observation group was more than the dosage of NPH in the control group, the number of daily injections in observation group was less than in the control group. The HOMA-B at the 7^th day, the FINS、HOMA-B、MBCI after treatment in the observation group were higher than in the control group. The incidence of hypoglycemia in the observation group (7.50%) was lower than that of the control group (20.00%). The difference was statistically significant (P< 0.05). After treatment, there was no statistical difference in BMI and the related indicators of maternal and child delivery outcomes between the two groups (P> 0.05).Conclusion The above two kinds of insulin can effectively control the blood sugar of pregnant women with diabetes and maintain the insulin level.However, the detemir effect is more obvious and its safety is higher.