Objective To investigate the population, community dominance, diversity, homogeneity and geographical niche of mosquitoes in China-Laos border, so as to provide advices for the prevention and control arboviral diseases and establish a reference for related ecological researches in these districts. Methods Surveillance were conducted in 12 counties and cities in China and Laos around border from 2012 to 2015. Adult mosquitoes were collected by overnight trapping with ovitrap light from August to October of each year. All captured mosquitoes were counted and identified in the laboratory and then computed the community composition, density, community index and geographical niche of mosquitoes. Results Total of 26 061 adult mosquitoes was captured and identified to 58 species of 13 genera in 3 subfamilies. Among them, 20 410 mosquitoes of 46 species of 11 genera in 3 subfamilies were captured in China and 5 651 mosquitoes of 36 species of 10 genera in 2 subfamilies were captured in Laos. The predominant species were Culex tritaeniorhynchus and Anopheles sinensis in the border areas of China and Laos. The proportion for Cx. tritaeniorhynchus in all captured mosquitoes were 52.05%(10 624/20 410)in China and 54.24%(3 065/5 651)in Laos(P>0.05). But the proportion of An. sinensis were higher in China(23.58%, 4 813/20 410)than in Laos(12.42%, 702/5 651)(P<0.05). There is no statistical significance in the average density between captured mosquitoes, Cx. tritaeniorhynchus and An. sinensis(P>0.05). There is no statistical significance in the dominance index, diversity index and homogeneity index(P>0.05). The order of mosquito diversity in counties along the border of China and Laos from high to low was Phongsaly, Louangphrabang, Luangnamtha, Houayxay, Oudomxay, Jinghong, Jiangcheng, Mengla, Mengxing, Simao, Menghai and Bengtai. The mosquitoes with maximum geographical niche were Cx. tritaeniorhynchus(B_i=0.810 9), Ar. subalbatus (B_i=0.746 1)and An. kochi(B_i=0.742 6)of 12 counties in the border of China and Laos, An. sinensis(B_i=0.880 2), Cx. tritaeniorhynchus(B_i=0.875 1)and Ar. subalbatus(B_i=0.809 5)in 5 counties of China border and Ar. subalbatus (B_i=0.944 7), Cx. tritaeniorhynchus(B_i=0.895 1), and An. barbirostris(B_i=0.880 8)in 7 counties of Laos border. Conclusion The populations of mosquitoes in the border of China and Laos were highly diverse, homogeneous distribution among communities, with stable composition and similar ecological characteristics. Culex tritaeniorhynchus and An. sinensis were the predominant species with maximum composition of community, density and geographical niche in these districts.