A study has been conducted on the maturation of ovary,spawningtype,ages of maturity，spawning waters and hermaphroditism of Lateolabtax japo-nicus (Cuvier et Valoncinnes?.The course of ovarian maturation is divided into sigstages and a recovered stage VI-IV' or IV'. Stage 1-Juveniles，stage II-includingimmature and recovered ovaries;stage III-ripening ovaries;stage IV-nearly ripe ovaries;stage V-ripe ovaries;stage VI-spent ovaries. After the fish releasesd thefirst batch of eggs,the ovaries regenerate into stage VI-IV' (or IV'),which conti-nue to develop rapidly into stage V'. About half a month later the ovaries developinto stage V'. If enviromental conditions are appropriate，then the another spawnmay take place. This fish are released two batches in a breeding season. The ova-ties develop to stage III in October as the age at first maturity，stage IV in Novem-fiber. The mature fish spawn at the middle of November and continue to Januaryof the next year. The fish spawn in the waters of the Yangtze River estuary andits adjacency with higher salinity nearby marine water. The salinity is about 22-26‰.The female and male reach the first maturity at 4 ages and 2 ages in yearold respectively. The individual absolute fecundity ranges from 3几2928-2211000eggs，averaging 1282327 eggs，and the individual relative fecundity ranges fronn185.27-847.71 eggs，averaging 408.03 eggs.