Objective To explore the heredity susceptibility of children to Kawasaki disease (KD) through studying expression and genomic density polymorphism of peripheral erythrocyte complement receptor-1 (ECRI). Methods Thirty cases of KD patients and 28 cases of healthy children were included in this study. The rates of red blood cell (RBC)-C3bRR and RBC-ICR were detected by method described elsewhere. The ECR1 activity and genomic density polymorphism were detected by Hind Ⅲ restriction enzyme digestion polymerase chain reaction-restriction fragment length polymorphism. Results Rates of RBCoC3bRR of KD patients during the acute phase was significantly lower than that of the control group (P < 0.01), and remained lower than the control group during the recovering phase (P < 0.05). The rates of RBC-ICR were significantly higher in KD patients than that of the control group (P < 0.05). Frequencies of HL and LL genotypes of KD patients were more than those of the control group (P < 0.01). A significant difference was found in the frequency distribution of ECR1 genotype between the two groups (P < 0.01). L allele frequency in the patient group was higher than that in the control group. Conclusions Depressed RBC immune function in KD patients may be linked to the high frequency of L allele, which implies the genomic density polymorphism of ECR1 play an important role in determining susceptibility to Kawasaki disease. (J Clin Pediatr,2010,28(2):160-163)