Abstract: OBJECTIVE To observe the diuretic effect of Tinglizi and study its possible mechanisms. METHODS Chronic heart failure model was established by the coarctation of abdominal aorta. After 8 weeks of operation, 40 CHF rats were divided into four groups randomly as follows: model group, Tinglizi groups(high-dose group, mid-dose group, low-dose group), with 10 rats for each group, and 10 sham operation rats ware taken as control(physiological saline, 2 mL). Adopting metabolism cage gathered the urinary output of the loading rats in 6 hours, and tested the urinary contents of Na⁺, K⁺ by microwave plasma torch atomic emission spectrometry (MPT-AES), tested the urinary contents of Cl^- by titration method. RESULTS Compared with the model group, high-dose group and mid-dose group could significantly increase the urinary output and contents of Na⁺, Cl^- in the CHF rats' urine; and high-dose group could reduce the contents of K⁺ in the CHF rats' urine. CONCLUSION Tinglizi manifests considerable diuretic effect. Its function mechanism had probably associated with inhibition of renal tubular to reabsorb water, sodium, and chloride, then caused an increase in water, sodium and chloride excretion.