Objective To investigate the clinical efficacies of Milrinone on cardiac function and blood-gas analytic indices in elderly patients with chronic heart failure.Methods During January 2013 to December 2016,50 elderly patients with chronic congestive heart failure admitted into the First People's Hospital of Qingdao Economic and Technological Development Zone were randomly selected and divided into the observation group (n=25) and the control group (n=25).The control group was given conventional treatment including diuretics,ACEI/ARBs,vasodilators,β-adrenergic receptor inhibitors and digitalis drugs,as well as anti-infection,fluid intake treatment and inhibiting the excessive activation of nerve-endocrine system.And Milrinone was taken as add-on to the therapy of control group in observation group.The changes in cardiac function,blood-gas analysis indices and adverse reactions were compared between the two groups.Results The total improvement rate of cardiac function was significantly higher in the observation group than in control group (92.0％ vs.76.0 ％,x2 =5.446,P＜ 0.05).The cardiac function indices,blood-gas analysis index and the level of CRP were significantly improved after treatment versus before treatment in both groups (all P＜0.05).And these improvements were significantly more superior in observation group than in control group (P＜0.05).Conclusions Milrinone can significantly improve the clinical efficacies in elderly patients with chronic heart failure.It can also improve the blood-gas indices and alleviate clinical symptoms,which seems to deserve more clinical application and promotion.