Objective To analyze the clinical effect of dagaglizin in the treatment of heart failure patients with type 2 diabetes mellitus and slight decrease in ejection fraction.Methods A total of 80 patients with type 2 diabetes com-bined with mild ejection fraction decline in heart failure admitted to Shaowu Municipal Hospital from October 2022 to October 2023 were selected as the study objects and divided into two groups by random number table method,with 40 cases in each group.The control group was treated with routine hypoglycemic and anti-heart failure treatment,and the observation group was treated with dagaglizin on the basis of the control group.Blood glucose level,cardiac function index and incidence of adverse reactions were compared between the two groups.Results After treatment,the blood glucose level of the observation group was lower than that of the control group,and the cardiac function indexes were better than those of the control group,and the differences were statistically significant(both P<0.05).There was no sig-nificant difference in the incidence of adverse reactions between the two groups(P>0.05).Conclusion The application of daglipzin can significantly improve the blood glucose level in patients with type 2 diabetes mellitus and slight de-crease in ejection fraction,and it is safe.