, a large anadromous species, mainly distributes in the continental shelf of the East China Sea and the main steam of Yangtze River. From July to August in each year, the pre-spawning individuals enter into the Yangtze estuary. Then they go against the water flow and will spawn in autumn of next year. The spawning locus is about 1 700 km away form the Yangtze estuary. After hatching, the yolk-sac larvae go downstream with the water flow and will arrive at the estuary in April and August of next year. Xupu, Changshu, a place at the Yangtze estuary, is a good site to monitor juveniles. So in years from 2002 to 2009, by a fixed stow net (set by the Yangtze Fishery Resources Commission for fishery monitoring) set in this site, we investigated the resources of juveniles. It was indicated that the emergence of the fish at Xupu, Changshu mainly occured from May to July, with the average period being 86.6 days (=8) average total length, body length and body weight were 25.2−40.1 cm, 23.2−314.8g, respectively. The numbers of specimens captured in each year were very different, and a decreasing trend occurred from the year 2002 to 2009. The periods (ten days as a unit) with maximum sampling number were also different, which ranged from the second ten days of May to the last ten days of June. The sizes of the juveniles were very different in the same period of different year, and the sizes of the specimens captured in the same year and same date also showed difference. Compared with the study in the four years (1987, 1990, 1991 and 1992) before the closure of the Three Gorges Dam, the time range that juveniles arrived at the Yangtze estuary showed no obvious difference(>0.05). However, the occurrence proportion in each ten days during the time from May to July varied. The high occurrence proportion was mainly in June before the closure, but after the closure it also occurred in May. The size of the juveniles was also different from pre-closure. It was speculated that the difference was caused by artificial enhancement and releasing, and variation of hydrological regime. ydrological condition was an important factor influencing the time consumption for the fish to migrate from spawning area to the Yangtze estuary.