Objective To investigate the association between the A9570G polymorphism of ACE2 gene and the relapse of steroid-sensitive nephrotic syndrome (SSNS) in Han childhood of Guangdong.Methods Ninety-two children with SSNS were selected from Guangdong Han nationality. According to the relapse frequency during the first year of the disease, 31 cases with more than 3 relapses were as frequency relapse group, 61 cases with less than 3 relapses were as non-frequent relapse group, and 60 healthy children were as control group. The gene distribution and allele frequency of ACE2 gene A9570G were observed by polymerase chain reaction-DNA direct sequencing technology.Results In female,the distribution of G allele frequency and GG genotype in SSNS group were significantly lower than that in the control group(39％ vs 65％, P<0.05; 27％ vs 50％, P<0.05). In male, the distribution of G allele/GG genotype in SSNS group was also significantly lower than that in the control group(35% vs 60%, P<0.05). Subgroup analysis found that the distribution of G allele frequency and GG genotype in female of the frequency relapse group were significantly higher than that of the non-frequency relapse group(58% vs 29%, P<0.05; 42% vs 19%, P<0.05), and the distribution of G allele/GG genotype in male of the frequency relapse group was significantly higher than that of the non-frequency relapse group (58% vs 24%, P<0.05).Conclusion The A9570G polymorphism of ACE2 gene was associated with the recurrence of children's SSNS, and the children with G allele were susceptible to recurrence.