Abstract: The experiment was conducted to investigate the possible effect of corticosterone treatment at different hatching time on the development of chicken embryos. Seven hundreds of AA broiler eggs were divided into 7 groups and randomly subjected to one of the seven treatments:corticosterone treatment (200 ng) at E0， E7 and E14， three positive control groups that injected with corn oil at E0， E7 and E14， and one negative control group. The incubation time，hatching ability and posthatching body weight were recorded.The blood samples were collected and the organs weight were measured after hatching.The results indicated that corticosterone treatment at E0 significantly reduced hatching ability(P＜0.05) and increased mortality of embryo.Corticosterone treatment at E7 shortened the incubation time (P＜0.05) and tended to reduce the hatching ability.The development of heart and liver were restrained by corticosterone treatment(P＜0.05).The result showed that the effect of corticosterone on the development of chicken embryo was age dependent.Moreover，the effect of injection had an adverse effect on embryos as well.