Abstract: The contents of endogenous hormones in empty-shell chestnut ovary and normal chestnut ovary during the period of embryo development were determined,and the effects of BR,GA3,PP333 on the endogenous hormone levels in ovary and top shoot of Chinese chestnut were analyzed by means of enzyme linked immunosorbent assay (ELISA).The results showed that,the contents of endogenous GA1+3,iPAs and the ratio of (GA1+3 +iPAs)/ABA in normal chestnut ovary showed as a “double peaks” model,while the content of endogenous ABA in ovary tended to reversely change by a small range.In contrast,the endogenous hormone contents and their ratio in empty-shell chestnut ovary showed no obvious peak,the contents of endogenous GA1+3,iPAs and the ratio of (GA1+3 +iPAs)/ABA appeared a descending trend while the endogenous ABA content appeared an ascending trend during whole embryo developmental period.The lower levels of endogenous GA1+3,iPAs and the ratio of (GA1+3 +iPAs)/ABA during the pollination period were related with poor pollination,and the decreases of those during the period of young embryo development could cause a serious lack of nutritious substances in ovary and a cease of young embryo development.Foliar spraying of BR (0.01 mg·L -1) could increase the levels of endogenous GA1+3,iPAs,ABA and the ratio of (GA1+3 +iPAs)/ABA in ovary and top shoot respectively,which showed a positive effect on embryo development.A considerable increase of endogenous GA1+3 level and a sharp decrease of endogenous ABA level in ovary and top shoot commenced with foliar spraying of exogenous GA3 (300 mg·L -1).Foliar spraying of PP333 (1000 mg·L -1) could obviously decline the content of endogenous GA1+3 in ovary and top shoot and increase the content of endogenous ABA in top shoot,which could be of benefit to embryo development of Chinese chestnut.