This study investigated the relationship between angiotensin-converting enzyme (ACE)gene insertion/deletion polymorphism and the occurrence, severity, prognosis of HSPN. The polymorphism of ACE gene in 103 HSPN cases and 100 healthy children was studied by using the polymerase chain reactions (PCR). Its relation to the clinical manifestation, pathological classification and prognosis of HSPN was analyzed accordingly. The results showed that: (1) there was a significantly higher frequency for DD genotype in HSPN children (P＜0.01) ; (2) DD genotype was more frequently seen in HSPN children with gross hematuria and massive proteinuria (P＜0.05), while DI genotype was more common in HSPN children group with renal insufficiency (P＜0.05); (3)although mesangial proliferative lesion was most frequently observed in 21 biopsied HSPN children,and DD genotype frequency was still higher in children with severe pathology (Class ⅢⅣ); (4)Ⅱ genotype was significantly frequent in HSPN children with complete remission in the follow-up of 32 HSPN children. It was concluded that the deletion allele of ACE gene might play a role, at least to some extent, in the occurrence, deterioration and progression in juvenile HSPN.