Abstract: Seed viviparity is one of the adaptative behaviors in mangrove plants. In this paper, the endogenous phytohormone abscisic acid (ABA) and gibberellin (GA₃), soluble sugar and starch contents were analyzed in different reproductive organs of viviparous mangrove plant Aegiceras corniculatum. The results indicated that during viviparous development stages, the content of ABA showed a maximum value at the bud stage ［(1.86±0.07)μg/g］, then decreased and reached a minimum value ［(0.75±0.07)μg/g］ at the seed stage. The content of ABA gradually increased as seed germinated. GA₃ level had a reverse trend of change with ABA level. It’s found that GA₃ increased and reached a maximum ［(12.60±0.05)μg/g］ at the seed stage, then decreased to a minimum ［(1.97±0.05)μg/g］ at the late seed germinating stage. Soluble sugar content increased firstly and reached the maximum in early seed germinating stage, and then decreased. Starch content was minimum in the bud, then increased gradually and reached a maximum in late seed germinating stage. Change pattern analysis of the endogenous ABA and GA₃, soluble sugar and starch contents during different viviparous development stages suggested that GA₃ and ABA regulating synergistically the carbohydrate metabolisms may be an important mechanism for the viviparity of mangrove seeds.