Abstract: Objective: To explore the interactive effects of kiss-1 gene polymorphism and serum leptin on susceptibility to polycystic ovary syndrome (PCOS). Methods: A total of 180 PCOS patients (PCOS group) and 180 non-PCOS healthy women (control group) were selected to compare demographic and baseline data,kiss-1 gene polymorphism,and serum leptin levels between the two groups.The serum leptin levels of patients with different kiss-1 gene polymorphisms were compared,and the relevant influencing factors of PCOS susceptibility were analyzed.The interaction between kiss-1 gene polymorphism and serum leptin on PCOS susceptibility and their types of action were also analyzed. Results: There was a statistically significant difference in body mass index and family history of PCOS between the PCOS group and the control group (P<0.05);the serum leptin levels in the PCOS group were higher than those in the control group,and the difference was statistically significant (P<0.05);after adjusting for body mass index and family history of PCOS,the rs4889 locus CC genotype and serum leptin were all associated with susceptibility to PCOS (P<0.05);the serum leptin levels in CC genotype patients at the rs4889 locus of kiss-1 gene were higher than those in GG and GC genotypes (P<0.05);the OR value of PCOS caused by serum leptin alone was 6.115,the OR value of PCOS caused by rs4889 CC genotype alone was 8.575,and the OR value of PCOS caused by coexistence of serum leptin and rs4889 CC genotype was 15.987.The interaction between serum leptin and rs4889 CC genotype and susceptibility to PCOS was a subproduct model,and serum leptin had a positive interaction on the utility of PCOS caused by rs4889 CC genotype. Conclusions: The rs4889 polymorphism of kiss-1 gene and elevated serum leptin can both increase susceptibility to PCOS,and there is an interaction between the two on PCOS susceptibility.This interaction conforms to the sub product model and exhibits a positive interaction.