Objective To describe the effect of loop diuretic on renal function in patients with chronic heart failure.Methods Data were of 211 impatients diagnosed as HF collected in a nested case-control study.The association of application of loop diuretic with renal function was assessed to identify whether loop diuretic was an independent risk factor of worsening renal function(WRF).To identify WRF,we defined serum creatinine level as a rise ≥26.5 μmol/L compared to the level at admission.Therefore,the subjects were divided into case group(serum creatinine level ≥ 26.5 μmol/L,n =66)and control group(serum creatinine level ＜ 26.5μmol/L,n =145).Results The doses of loop diuretic were higher in the case group([385.17 ± 49.37]mg)than the control group([244.50 ± 34.82]ag)(P ＜ 0.05),but it was not independent risk factor of WRF (P＞0.05).Creatinine level and NYHA class at admission were independent risk factor for WRF,with OR of 2.248(95 ％ CI:1.088-4.647)and 2.485(95 ％ CI:1.385-4.459)respectively(Ps ＜ 0.05).Conclusion The doses ofloop diuretic were not independent risk factor of WRF,creatinine level and severity of HF at admission are the most important predictors of the occurrence of WRF.