Abstract: The anatomy structure and histology of the ovary of Penaeus monodon from the north of South China Sea were studied using anatomy and histology methods. The results indicated : (1) the anatomy structure of ovary consists of a pair of anterior lobe, eight pairs of lateral lobes and one pair of backward outstretched lobe. The second pair of lateral lobe is the biggest in the eight pairs of lateral lobes of the mature ovary. The terminal of sixth lateral lobes have a transparent oviducts which pass through the body wall of the thorax to the ovipores which lie in the coxa of the third pereiopod. (2) The results of the histology structure show that the ovary consists of ovarian wall, central tube and egg chamber. The ovarian wall is composed of epithelium layer, loose connective tissue, basement membrane and differentiation epithelium from out to in.The central tube produces a lot of oogoniums. The egg chambers contain the oocyte at different development phases.