The changes of individual morphology and oocyte characteristics of conger eel during the development of ovary were studied; meanwhile, the nutritional components of ovary, liver and muscle were investigated. The results showed that the ovary development of conger eel could be divided into 5 stages:the single-layer follicular cells stage, the oil drop stage, the yolk filled stage (early, middle and late), the nucleus polarized stage, and the mature oocyte stage. The diameter of the oocyte, nucleus, oil drop, and the yolk globule gradually increased with the development of the oocyte. The initial location of oil drops was around the nucleus, and preceded the yolk sphere. The oil drops were distributed in a ring shape and gradually extended toward the cell membrane through the oocyte development. The initial occurrence site of yolk sphere was in the cytoplasmic layer around the cell membrane, which was distributed in a ring shape as the oocyte developed and extended toward the nucleus. The gonadosomatic index, hepatosomatic index, ocular index, and anal length index all showed positive correlations during development. The digestive gut index was negatively correlated with gonadosomatic index, hepatosomatic index, ocular index, and anal length index. The changes in nutritional composition indicated that the fat storage location is in muscle, and the fat transportation plays a critical role during the ovary development. The results of this study give an essential reference for the artificial reproduction of conger eel.