Objective To understand larval breeding and species composition of dengue vector mosquitoes in residential area of Gengma county during the seasonal peaks, in order to provide a scientific basis for control of mosquitoes and mosquito-borne diseases. Methods In August 2016, the Breatu index method was used to investigate the breeding and composition of Aedes larvae in all types of water containers in 6 residential areas of Gengma county. SPSS 19.0 software was utilized for data analysis by Chi-square test, Chi-square partition test and Fisher precise probability to explore the significance of species composition and positive breeding. Results In this study, a total of 361 households were surveyed, among which 62 households were confirmed positive. In total, 1 216 water containers were found, of which 106 were positive. The Breatu index(BI), house index(HI) and container index(CI) were 29.36, 17.17, and 8.72%, respectively. All of them were the highest in Mengjian township, 85.00, 60.00, and 18.48%, respectively. The BI of 4 sites reached the outbreak level for dengue fever. The main and positive water containers were buckets, which were 408 and 31 respectively. The positive rate of Aedes breeding in different types of containers was analyzed by Chi-square partition method. The highest positive rate of used tire was 32.89%(25/76) (α=0.004, P=0.002). Compared with Qingshuihe port, the composition of Aedes species in Mengding town was not statistically significant by Fisher method (P=0.123). Conclusion Aedes aegypti and Ae. albopictus, the vectors for dengue fever, were found in Gengma county, especially more predominant than that of Ae. albopictus in Mengding township and Qingshuihe port. The distribution range of Ae. aegypti showed the tendency of further expanding. The main types of Aedes breeding containers was used tires, followed by temporary containers, waste bottles, etc. These types of containers should be drained first, supplemented by adulticiding during the vector control operations.