Abstract: Objective To study the effects of manganese chloride on reproductive function of male mice,and explore the dose effects,and time-effects.Methods The mice were randomly divided into three treatment groups with manganese chloride(7.5,15.0,30.0 mg/kg)and 1 control group with NS.To observe the weight coefficient of testis after 5 different periods(3,7,14,28,56d)i.p.administration MnCl₂(7.5,15.0,30.0mg/kg),the reproductive ability of male mice,changes of cross section area of seminiferous tubule and quantity of seminiferous epithelium cell were investigated after 56 d of manganese exposure.Results After 56day manganese exposure,the weight coefficient of testis in 15,30 mg/kg groups had distinctive difference as compared with control group(p<0.05,p<0.01);the exponent of birth and the radio of dead fetus in 30 mg/kg group had significant difference as compared with control group(p<0.05,p<0.05);and the average of live fetus and ratio of nidation in 3 manganese exposure groups had distinctive difference as compared with control group(p<0.01);cross section area of seminiferous tubule and quantity of seminiferous epithelium cell as compared with control group;the difference had statistical significance(p<0.01).Conclusion The reproductive ability of male mice,it was the most serious in 30 mg/kg group after 56-day manganese exposure.