OBJECTIVE： To investigate the effects of olmesartan medoxomil on cardiac function， plasma N-terminal pro-brain natriuretic peptide （NT-proBNP） and serum interleukin-23 （IL-23） in patients with chronic heart failure （CHF）， and to evaluation its safety. METHODS： A total of 40 CHF patients selected from Lianshui County People’s Hospital of Jiangsu Province during Dec. 2014-May 2016 were divided into control group and observation group according to random number table， with 20 cases in each group. Control group was given Enalapril maleate tablets with initial dose of 5 mg， po， qd （increasing gradually after one week， limiting dose of 20 mg/d）+Metoprolol tartrate tablets 25 mg， po， bid+Isosorbide mononitrate tablets 40 mg， po， qd+Furosemide tablets 20 mg， po， bid. Observation group was additionally given Olmesartan medoxomil tablets 20 mg， po， qd， on the basis of control group. Both groups received treatment for consecutive 8 weeks. Cardiac function indexes [LVEDD， LAD， IVST， LVPWT， LVEF， early diastolic peak E filling velocity/late diastolic peak A filling velocity （E/A）]， plasma NT-proBNP and serum IL-23 levels were observed in 2 groups before and after treatment. The incidence of ADR was recorded. RESULTS： Before treatment， there was no statistical significance in cardiac function indexes， plasma NT-proBNP or serum IL-23 levels between 2 groups （P＞0.05）. After treatment， LVEDD， LAD， plasma NT-proBNP and serum IL-23 levels of 2 groups were decreased significantly， while LVEF and E/A levels were increased significantly； the observation group was significantly better than control group， with statistical significance （P＜0.05）. There was no statistical significance in IVST or LVPWT levels between 2 groups before and after treatment， and there was no statistical significance in the incidence of ADR between observation group （25.00％） and control group （20.00％）（P＞0.05）. CONCLUSIONS： Olmesartan medoxomil can decrease the levels of plasma NT-proBNP and serum IL-23 in CHF patients， and improve cardiac function with good safety.