Objective To study the clinical significance of serum cystatin C(Cys-C) for early diagnosis of renal injury induced by asphyxia in neonates. Methods Neonates with asphyxia were divided into mildly asphyxiated group(192 cases)and seriously asphyxiated group(34 cases) by Apgar scores of 1 minute after birth,meanwhile 39 cases of no asphyxia of newborn as control group.The peripheral vein blood samples of neonates were collected,and serum Cys-C was detected.It was compared with serum creatinine( Cr) and urea ( BUN) with Kruskal-Wallis H Test.The related factors of Apgar score such as Cys-C,Cr,BUN and so on were analyzed by Logistic regression analysis. Results 1)The level of Cys-C was (2.54±0.48)mg/L,(2.16±0.45)mg/L,and (1.53±0.27)mg/L in seriously asphyxiated group,mildly asphyxiated group and control group,respectively.The level of Cr was (102.32±32.64)μmol/L,(89.35±26.24)μmol /L and (69.03±22.00)μmol /L respectively.The levels of BUN was (9.26±4.29)μmol/L,(8.31±4.50)μmol /L and (5.31±3.01)μmol/L,respectively.Kruskal-Wallis H tests indicated that there were significant differences between seriously asphyxiated group,mildly asphyxiated group and control group(P<0.01).2)Logistic analysis indicated that the level of serum Cys-C had the least OR value. Conclusions The less Apgar score is,the higher levels of serum Cys-C,Cr and BUN are.There is a best relationship between the Apgar score and the level of serum Cys-C in early examination of asphyxiated neonates.