Objective:To study the effects of Daidzein on immunity organ.Methods:The method of weighed up avoirdupois,mensurated the avoirdupois and spleen and thymus gland of the mice.Result:It was found that Daidzein obviously increased the avoirdupois and spleen index and thymus gland index of the mice.Conclusion:Daidzein has effects on increasing avoirdupois of immunity organ.