In this study, the morphological changes of ovary development and variation of correlated plasma sex steroids levels were detected in Alosa sapidissima. The result shown that Alosa sapidissima belongs to the non-synchronized multiple batch spawner; based on size, shape and external color, the development of ovary was divided into six stages; according to changes of inner structures, yolk accumulating and development of follicle cells, the oogenesis could be divided into six phases. There were no significant differences about hepatosomatic index (HSI) and condition factor (CF) during the ovarian maturation cycle, but gonadosomatic index (GSI) and 17β- estradiol (E2) were found to increase during the peak phase of vitellogenic growth corresponding to the ovary development.