1. 423 postlarvae and juveniles of Auxis Curvier, with body length 3.12--17.5mm, were collected in the Dong Hai, China, during the years of 1971-1980. 2. The specimens were identified as Auxis thazard, Auxis tapeinosoma and Auxissp. and the main characteristics for identification are the pigment distribution on thecaudal peduncle and the ratio of different parts of the body. 3. The spawning season and ground of Auxis in Dong Hai is little Known.According to observation and estimation, the spawning season may possibly be inMarch to september, chiefly in July and August. The area of distribution is mainlyto the south of 28°N and the west of 125°E during March to July and to the north of28°N during August and September. 4. The spawning migration of Auxis is closely related to the Kuroshio WarmCurrent and also under the influence of fresh waters from Chang Jiang river as well.They spawn and move north with the prevalence of Kuroshio at the temperature of27-29℃, salinity of 33-34‰ and in the depth of 60-100 metres.