Objective To study the effect of low-level ozone on reproductive physiology of mice. Methods Low-level ozone was created by 15W ultraviolet light. The mice in experimental group and control group were fed in low-level ozone environment or normal environment respectively for 7 weeks. The weight variations of both groups were observed, and estrous cycle of female mice was determined by exfoliative cytoscopy of vagina.Then the sperm abnormality test and the micronucleus test of early spermatids were performed in both groups;serum samples were taken for sex hormone determination by radioimmunoassay kit;specimens of spermary and ovary were taken for histopathological analysis. Results No significant difference was found in the weight variation of female mice,but male mice of experimental group were lighter than those of control group;the difference of the estrous cycle of female mice was not significant;no significant difference was observed in sperm abnormality,micronucleus of early spermatids and serum sex hormone level;no histopathological abnormality was observed in both groups. Conclusion Low-level ozone created by ultraviolet light in our research has no effect on reproductive physiology of mice.