Objective To explore the influence of fluoride exposure, estrogen receptor α (Erα) gene polymorphism and the interaction of them on reproductive hormones in male living in endemic fluorosis villages in China.Methods A cross sectional study was conducted in Tongxu county in Henan Province, China in 2011-2012.Adults aged 18-55 years old who were born and grew in endemic fluorosis villages and control villages or lived there at least 5 years were recruited using cluster sampling.They were divided into defluoridation villages (DFPG), high fluoride villages (HFG)and control villages (CG) respectively.Provided fasting blood sample and instant urine sample.We detected the levels of serum GnRH, FSH, LH, E2,T and urine fluoride, and then analyzed the laboratory data.Results ①GnRH and T levels in male from HFG were significant lower than that from DFPG and CG (P<0.05).Serum levels of E2 and FSH in male from HFG were significantly higher than that from DFPG and CG (P<0.05).②In HFG, serum T level in male carrying Pp genotype of Erα PvuⅡ was significantly lower than that in male carrying pp genotype (P<0.05), and serum FSH level in male who carried C/C genotype of Erα rs3798577 was significantly lower than that in male who carried C/T or T/T genotypes (P<0.05 respectively).In DFPG, serum FSH level in male who carried pp genotype was significantly higher than that in male carrying PP or Pp genotype of Erα Pvu Ⅱ(P<0.05 respectively) ③ Serum GnRH in CG and DFPG was significantly higher than that in HFG in male who carried Pp, xx and C/T genotype of Erα Pvu Ⅱ, Xba Ⅰ and rs3798577 (P<0.05 respectively).Serum GnRH in male carrying C/C genotype of Erα rs3798577 in CG was significantly higher than that in HFG.Serum FSH level in CG was significantly higher than that in DFPG in male carrying PP genotype of Erα Pvu Ⅱ.Serum FSH level in male who carried Pp genotype of Erα Pvu Ⅱ was DFPGDFPG>CG.Serum T level in male who carried Pp genotype in CG and DFPG was significantly higher than that in HFG.Conclusion ①Long-term fluoride exposure in drinking water may influence the reproductive hormones in males living in endemic fluorosis villages.② The interaction between fluoride exposure and Erα polymorphism may affect the serum hormone of HPG axis in male.③Serum T level was reduced in male from HFG who carried Pp genotype, serum level of FSH increased in male from HFG who carried T/T genotype.