Abstract: Objective To investigate the effects of different thyroid function in elderly patients with chronic heart failure on clinical prognosis and cardiac function. Methods The 247 elderly patients with CHF which has baseline thyroid function tests were chosen.The cases were divided into hypothyroidism group(43 cases),subclinical hypothyroidism group (79 cases) and normal thyroid function group(125 cases) according thyroid function.The general clinical data,duration of heart failure,cardiac function and readmission rates,the incidence of acute heart failure,acute coronary syndrome incidence,mortality,and other indicators of the incidence of the composite endpoint between the three groups were compared. Results There were no significant difference in age,gender and cardiovascular risk factors (including hypertension,hyperlipidemia,diabetes,smoking),medications and the like in three groups of patients(P＞0.05).Euthyroid group average duration of heart failure was(3.1±0.7) years,subclinical hypothyroidism average duration of heart failure was(4.7±0.9) years,the average duration of heart failure hypothyroidism group was(5.9±0.7) years.The difference between the three groups of heart failure duration was significantly(F=4.126,P＜0.05).The prevalence of thyroid dysfunction with heart failure duration＞5 years was 75.9%(66/87),3-5 years was 54.1%(33/61),＜3 years 23.2%(23/99).With the extension of the duration of heart failure,the prevalence of thyroid dysfunction gradually increased(χ²=52.031,P＜0.01).The admission rates,heart failure exacerbation,mortality and incidence of the composite end point in patients with hypothyroidism and sub-clinical hypothyroidism were significantly higher than those in normal thyroid function group(P＜0.05),and indexes above in hypothyroidism group were significantly higher than those in the subclinical hypothyroidism group(P＜0.05).NYHA difference in three groups were significantly different(χ²=19.152,P＜0.01),with the loss of thyroid function,the proportion of Ⅱ grade of patients with cardiac function is small,while the proportion of patients with grade Ⅲ and Ⅳ cardiac function increased. Conclusion Hypothyroidism and elderly patients with chronic heart failure NYHA has relevance and monitoring thyroid hormone levels have predictive value for heart function and its prognosis.