Objective To study the relationship between throid hormone and chronic heart failure in patients and its clinical significance. Methods The free thriiodothyronine( FT3 ), the total thriiodothyronine(TT3 ), the free thyroxine(FT4 ), the total thyroxine (TT4 ), the rebellion thriiodothyronine ( rT3 ), the thyroid stimulating hormone (TSH) in 100 patients with chronic heart failure and 50 normal people were determined by particle glimmer. Results The levels of T3 in patients with chronic heart failure were markedly lower than those in normal controls;The heart failure in low thriiodothyronine state case was severe. Conclusion The level of T3 in elderly patients with chronic heart failure was decreased, and it was correlated with the severity of heart failure.