The development process of the circulatory system of Penaeus chinensis has been studied w ith tissue method. At the third stage of nauplius, originating from the part of carapace rudiment, the mesoderm cells of each side of ventral- lateral part of the larva divide quickly and extend towards back to form the heart rudiment cells. Then some of them migrate medially to form a mesodermal plate above the back of the mid- gut. After that, the plate curls towards back to form the heart. Meanwhile, the others extend outwardly to make contact with each side of lateral part and form the pericardial cavities. At the fifth stage of nauplius, the wall of heart slits inward directly to form the ost ia. The shape and the structure of heart improve with the development of the larvae. After the first stage of zoaea, the cells of heart wall develop into myocardial cells. Subsequently, one thin layer of adventit ia formed by the connective tissue cells encloses the myocardium. At the post larva stage, the appearance and the tissue structure of heart are similar to those of adult. The measure and time of development of dorasl abdominal artery are similar to those of heart. The formation of median dorsal artery includes two parts: one part near heart is extended by the heard of heart; another part far away from heart is formed by mesodermal cells in front of nauplius back; hemocytes are observed at the f irst nauplius.