Objective:To investigate the effect of excessive additive iodine intake on reproductive organs of male weanling rats.Methods:One hundred and three male weanling rats were fed with feedstuff containing 0,0.5,1,2.5,and 5-fold higher dosage of iodine in standard iodine-additive salt,i,e.200,300,400,700,and 1200 μg/kg,respectively,for 130-136 days.The number of rats taking different dosages of iodine was 20,21,21,21,20 respectively.The rats fed 200μg/kg of iodine were taken as the control group.For all groups,their structural changes of reproductive organs and sperm quality were evaluated.Results:The three experiment groups fed with 1,2.5,and 5-fold higher dosage iodine showed apparent reduction in testicular weight (P＜0.05-0.01) by 10.76％,14.58％ and 25.35％,respectively,compared with the control.But significant reduction in testis/body weight ratio was only observed in the 5-fold higher dosage group.The sperm concentration and total sperm count declined in four experiment groups fed with 0.5-5 fold higher dosage of iodine.The sperm concentration was reduced by 6.59％,22.53％,17.35％ and 18.06％ respectively.The percentage of sperm with normal and abnormal form significantly changed (P＜0.05).The addition of different doses of iodine showed no apparent adverse effects on other reproductive organs or sperm viability.Conclution:These results indicated that excessive iodine intake might cause potential hazards on reproductive organs of male rats with respect to spermatogenesis.