in eastern China plains, and has also formed some new populations in alien rivers due to extensive introduction for aquacultural or ecological purposes. To understand the genetic resource of wild bighead carp around the world, genetic variation of Chinese native populations from Yangtze River (YZ) and Pearl River (PR), national introduced populations from Amur River (AMUR), and two alien introduced populations from Danube River (DAU), Europe, and Mississippi River (MIS) and North America were analyzed by AFLP. The results showed Nei's genetic diversity () of the native populations YZ and PR were 0.0394±0.1221 and 0.0529±0.1236, respectively, while 0.0233±0.0883, 0.0122±0.0619 and 0.0134±0.0614 for the introduced AMUR, DAU and MIS populations. Genetic diversity of the introduced populations was lower than the native populations because continuous genetic bottle-neck effects happened for the introduced populations during the progresses of introduction, adaption and establishment of new populations in alien areas. AMOVA showed the variance within populations was 68.52% while interpopulations variance was 31.48% for all bighead carp populations. The <0.01), while of native populations and introduced populations was 0.155 0 (<0.01). There was significant difference among native populations and introduced populations, which may reflect different genetic background and genetic drift, ecological pressure and natural selection exerted on them. The above results may be helpful to monitor genetic variation trends for both native populations and introduced populations in alien rivers in the future.