Objective To analyze the effect of insulin detemir+insulin aspart on postoperative blood glucose control in patients with diabetic rectal cancer.Methods The clinical data of 120 patients with diabetic rectal cancer admitted to Quanzhou First Hospital from January 2023 to April 2024 were retrospectively selected.They were divided into two groups according to different postoperative glucose control treatment methods,with 60 cases in each group.The two groups were treated with routine treatment after operation,the control group was treated with subcutaneous injection of insulin detemir before bedtime,and the study group was treated with preprandial injection of insulin aspart on the ba-sis of the control group.The blood glucose levels,oxidative stress indexes and adverse reactions were compared be-tween the two groups.Results Before treatment,there were no significant differences in blood glucose levels and oxi-dative stress indexes between the two groups(all P>0.05).After treatment,the levels of fasting plasma glucose,2-hour postprandial plasma glucose and malondialdehyde in the study group were lower than those in the control group,the level of superoxide dismutase was higher than that of control group,and the differences were statistically significant(all P<0.05).There was no significant difference in the incidence of adverse reactions between the two groups(P>0.05).Conclusion Insulin detemir combined with insulin aspart can significantly reduce blood glucose level and im-prove oxidative stress in patients with diabetic rectal cancer after operation,and the risk of adverse reactions is low.