Objective To study the clinical efficacy of irbesartan hydrochlorothiazide combined with small dose thyroxine in the treatment of severe heart failure in the elderly. Methods 100 elderly patients with severe heart failure were selected as the research object (from January 2013 to December 2016). They were randomly divided into the control group and the experimental group, with 50 patients in each group. Patients in the control group received routine treatment, including diuretic therapy, cardiac treatment, and anti heart failure treatment. The experimental group was treated with low-dose thyroxine combined with irbesartan and hydrochlorothiazide on this basis. The clinical effects of the two groups were compared and analyzed. Results After the corresponding treatment, the number of invalid cases in the experimental group was 6 cases, 16 cases were effective, 28 cases were effective,and the total effective number was 44 cases. In the control group, the number of invalid cases was 15. The effective rate of the treatment group was 88.0％, which was significantly higher than that of the control group 70％, which was statistically significant (P<0.05). After treatment, the left ventricular ejection fraction, the level of four and three, and the level of serum thyroid stimulating hormone in the experimental group were significantly higher than those before treatment, with statistical difference (P<0.05). Conclusion Small dose thyroxine combined with irbesartan and hydrochlorothiazide is effective in the treatment of severe heart failure in elderly patients, and can significantly improve the heart function of patients, and has the significance of further clinical promotion.