Objective To observe the improving effect of ca rvedilol on cardiac function in pati ents with congestive heart failure(CHF)of dilated cardiomyopathy(DCM).Methods Total 60patients with chronic heart failure secondary to DCM were divided into two groups ran-domly,namely carvedilol group addi tionally treated with carvedilol(the test group),conventional group receiving placebo(the controls).The left ventricular fraction shorteni ng(FS),ejection fraction(EF),stroke volume (SV),left ventricular diastolic dimension(LVDD)were measured with echocardiography,we re measured before and after 4-month treatment.Results After treated for 4months ,the cardi ac function improved greatly in both groups.In t he test group,LVDD,EF and 6-minute walking distance improved more signi cantly compared to the con-trols.Conclusion Carvedilol can improve cardiac function and exercise tolerance in the pa tients with CHF of DCM obviously.