Abstract： Objective To investigate the influence of insulin aspart on insulin resistance and adverse pregnancy out-come in patients with gestational diabetes mellitus.Methods A total of 140 patients with gestational diabetes mellitus admitted to Dongchangfu Maternal and Child Health Hospital of Liaocheng from March 2020 to March 2023 were se-lected as the study objects,and they were divided into two groups with 70 cases each according to random number table method.Control group treated with metformin,observation group treated with aspartate insulin.The blood glu-cose and insulin resistance index and pregnancy outcome of two groups were compared.Results After treatment,the levels of fasting plasma glucose,2-hour postprandial plasma glucose and glycated hemoglobin A1c in the observation group were lower than those in the control group,and the differences were statistically significant(all P<0.05).After treatment,the insulin resistance index of the observation group was lower than that of the control group,and the islet β cell function index was higher than that of the control group,and the differences were statistically significant(both P<0.05).The incidence of adverse pregnancy outcome in the observation group was lower than that in the control group,and the difference was statistically significant(P<0.05).Conclusion Aspartate insulin treatment for patients with ges-tational diabetes mellitus can restore normal levels and protect maternal and infant health.