Abstract： Objective To study the effects of trimetazidine on cardiac function in type 2 diabetes mellitus patients with heart failure. Methods Ninty type 2 diabetes mellitus patients with heart failure were randomly divided into two groups (45 patients in control group,45 patients in treatment group). All patients in both two groups received routine therapy in order to have blood glucose under control,the treatment group was treated with trimetazidine 20mg po Tid ,treatment for 6 months. Before and after treatment ,two groups were detected left ventricular end-diastolic diameter (LVEDD), left ventricular end systolic diameter (LVESD) and left ventricular ejection fraction (LVEF), and the clinical efficacy were evaluated. Results Ater treatment, the rate of total efficiency was 68. 9% in control group, and it was 86. 7% in treatment group. The clinical efficacy of treatment group was significantly better than control group(P＜0.05) ;Ater treatment,LVEDD,LVESD were significantly reduced than those before treatment(P ＜0.05) ,LVEF was significantly higher than that before treatment (P ＜0.05);After treatment,LVEDD, LVESD in treatment group was significantly reduced than those in control group, LVEF was significantly higher than control group (P ＜ 0.05).Conclusion Trimetazidine can significantly improve the cardiac function in type 2 diabetes mellitus patients with heart failure.