Objective To study the change of mid-regional pro-adrenomedullin(MR-proADM) level in patients with chronic heart failure and its significance. Methods Randomly selected 330 patients with chronic heart failure, including 120 cases of grade Ⅱ and Ⅲ, 90 cases of grade Ⅳ, 90 cases were selected., Within 24 h after the entry of the group and 7 d after symptom relieved, serum N-terminal pro-B-type natriuretic peptide(NT-proBNP), MR-proADM, cardiac ultrasound(left ventricular diameter(LVEDD) and left ventricular function(LVEF)) were measured.Ninety physical examination in the same period as healthy control during the same period.The change of MR-proADM level in patients with chronic heart failure and its significance were analyze. Results Compared with the healthy control group, the level of MR-proADM in patients with chronic heart failure(grade Ⅱ: (641.55±106.34) pmol/l; grade Ⅲ: (684.46±101.33) pmol/l; grade Ⅳ: (737.81±479.37) pmol/l) was significantly higher than that in the control group(610.22±60.84) pmol/l), the difference was statistically significant(F=5.33, P=0.001). At the same time, the level of MR-proADM was increased with the aggravation of heart failure, after drug treatment will decline((608.09±100.81), (617.64±94.32), (642.22±163.53) pmol/L). And MR-proADM levels were significantly positively correlated with NT-proBNP levels and NYHA classification in patients with heart failure(r=0.194, P=0.003; r=0.206, P=0.000). Conclusion MR-proADM has important guiding significance in the diagnosis, classification of patients with chronic heart failure. Key words: Chronic heart failure; Mid-regional pro-adrenomedullin; Cardiac function classification