Objective To investigate the diagnostic value of serum Cystatin C for early detection of renal damage in patients with liver cirrhosis. Methods 24-h creatinine clearance (CCr), serum level of cystatin C (CysC) and serum creatinine were measured in 76 patients with cirrhosis and t-test,Pearson's correlation test and ROC curve were used to evaluate the diagnostic significance of Cys C.Results The increase in Cys C level was associated with a decrease of CCr in the patients. Both Cys C and SCr were inversely correlated with CCr ( CysC: r =- 0. 763, P < 0. 001; SCr: r=-0. 571,P<0.01). Meanwhile, the area under the ROC curve was significantly higher in Cys C than in SCr (0. 830 vs. 0. 612). Conclusion Cystatin C is a more accurate and sensitive marker of renal diagnosis in liver cirrhosis. Detection of Cys C level in cirrhotic patients is of great significance for the prevention of liver-kidney syndrome.