Abstract: The fluctuations of amino acid,mineral element and carbohydrate contents inthe ovary and involucre during fertilization,young embryo and cotyledon development inempty shell chestnut and normal chestnut were studied.The results showed that the total amino acid contents of empty shell chestnut in the ovary and involucre were lower14.42% and 38' 83% than those of normal chestunuts, respectively.Mineral elements,such as K, Mg, B, Zn, in the involucre were lower 37.5%, 53.33%, 38.10%, 25.63%than those of normal chestnuts,respectively.The contents of reducing sugar and starcho f empty shell chestnut in the involucre were lower 46.15% and 7.83% respectively,and in the ovary were lower 13.08% and gi.37%, respectively than normal chestnut.Lack of some mineral elements,organic substance in the development process of youngembryo and cotyledon, the syntheses of certain physiologicaly active substance, thetransmission and accumulation of some nutritional substances,are reasons of the occurrence of empty-shell chestnut.