To evaluate the clinical effects of milrinone in patients with severe heart failure, heart function and clinical observations were performed on 25 patients with severe congestive heart failure treated with domestic intravenous milrinone for 15 days. Results showed that the total response rate to milrinone was 96% while 60% of them had significant improvement. Heart function and diameter of left atrial, left ventricle, and right ventricle were measured by pulsed Doppler and M-mode echocardiographg before and after the treatment. The systolic function of the left ventricle (such as SV, CO, EF, FS, IVST, PLVWT) was significantly improved. The diastolic function of the left ventricle (such as E peak, A peak, IRT) was also improved. Diameter of left atrial, left ventricle, and right ventricle was significantly reduced. The heart rate and blood pressure remained unchanged. No obvious side-effect was found in our observation. The domestic intravenous milrinone is a drug of choice for the management of patients with severe congestive heart failure.