Japanese eel (Anguilla japonica) is a commercially important fishery species throughout eastern Asia. The effective management of this resource necessitates accurate information on the ecology of this migratory species, much of which is currently lacking. In this study, we investigated the demographic structure and growth of catadromous Anguilla japonica from the Yangtze River Estuary, China. We captured 121 individuals from the Jingjiang reach of the Yangtze River throughout October 2012. We found that males and females differed significantly in several key characteristics. Females, which were more numerous than males with an overall sex ratio of 78:43, were significantly older (5.5±1.18 years) and larger (654.9±67.6 mm, 522.1±176.2 g) than males (5.0±1.23 years, 527.8±40.1 mm、249.8±63.7 g) and had on average faster growth rate (110.48±12.76 mm year^-1) than males (96.46±16.75 mm year^-1). Although males reached a smaller theoretical asymptotic length (918.88 mm) and mass (1432.89 g) than females (610.04 mm, 385.87 g). The sampled eels at our study site were on average younger and larger than those of other populations at other sites, suggesting that maybe this region is more suitable for the growth of A. japonica;(5)The growth difference between female and male may come from their different growth strategies.