Objective　To investigate the species composition and population density of mosquitoes before impoundment and after recession in the fluctuating zones of the Three Gorges Reservoir region and to provide a basis for surveillance of mosquito vector and mosquito-borne diseases. Methods　Four surveillance sites were established in the typical fluctuating zones at upper, middle, and lower streams of the Three Gorges Reservoir region. For each surveillance site, 3 lamp trapping cages were placed at each of the three different altitudes (10 m altitude difference). The surveillance was carried out before impoundment and after recession in 2010. Results　In 2010, a total of 101 mosquitoes were captured with 90 lamp-times, which belonged to 4 species: Culex tritaeniorhynchus, which accounted for 21.78% (n＝22); Anopheles sinensis, which accounted for 16.83% (n＝17); Cx. pipiens, which accounted for 16.83% (n＝17); Armigeres subalbatus, which accounted for 6.93% (n＝7); other species, which accounted for 37.63% (n＝38). Conclusion　The fluctuating zones of the Three Gorges Reservoir region provide breeding sites for mosquitoes. Mosquito density is low in these areas, and shows a decreasing trend with increasing altitude. Vector of Japanese encephalitis, Cx. tritaeniorhynchus, and malaria vector, An. sinensis, exist in these areas.