Observation on the ovary sections of Ilisha elongata ( Bennett) was taken. It shows that it s breeding season extends from May to July, during which period the ovary is variously found to be in stages . , . , .- . . and .. ( recovering) . In August and September, the ovary is in a stage of degeneration after spawning. From October to February of the following year, the w inter ovary is in stage ò . In March and April there is the prespawning spring ovary. In the course of development of oocytes of Ilisha elongata, the nucleus increases in volume more markedly than the cytoplasm during the small growth stage, but during the great growth stage, with the accumulation of yolk substances, the volume of the cytoplasm increases rapidly with a correspondingly sharp drop in the nucleus-plasma ratio, which approaches a minimum ratio as the oocyte approaches full maturity. In the development of oocytes, there are two layers of membrane outside the plasm membrane, but in the late stage of vitellogenesis the zona radiata of the oocytes degenerates, and there is only a layer of gluey membrane. Evidently the development of oocytes in the ovary of Ilisha elongata is in a successive process and female seems to be able to spawn twice in one spawning season.