Abstract: Objective：To investigate the changes of serum cystatin C in children with Kawasaki disease and its role in the pathogenesis of coronary artery lesions.Methods：fourty two children with Kawasaki disease and 21 febrile controls were studied. The duration of Kawasaki disease was divided into three phases：the acute phase, the subacute phase and the convalescent phase.Serum cystatin C was detected by immunoturbidimetry in three phases respectively.The coronary artery lesions were checked by doppler echocardiograph.Results：The levels of serum cystatin C in Kawasaki disease decreased significantly in acute phase and sub-acute phase(P<0.05), and the levels of serum cystatin C of group with coronary artery lesions decreased more significantly than those of group without coronary artery lesions. The levels of serum cystatin C in Kawasaki disease in recovery phase were not significantly lower than those of the control group. Conclusion：The levels of serum cystatin C droped obviously in the acute phase of Kawasaki disease, especially in the group with coronary artery lesions, and can’t reincrease in sub-acute and convalescent phases of Kawasaki disease,which may be related to the degree of coronary artery injury, so monitoring serum cystatin C may predict risk for the pathogenesis of coronary artery lesions in children with Kawasaki disease.