Objective To determine the species composition and population dynamics of mosquitoes in Wenzhou city, Zhejiang, China, to analyze the population trends in different mosquito breeding environments, and to provide a scientific basis for the city mosquito control operations. Methods Night light traps were utilized to conduct monthly monitoring in 11 counties of Wenzhou city from April to November during 2010-2013. Results A total of 14 597 adult mosquitoes were captured during the monitoring period, where Culex pipiens pallens was the predominant species, accounting for 82.44% of the total number of mosquitoes. The peak of adult mosquito density appeared from July to August, the highest density appeared in August or 2011, which is 2.83 mosquitoes per light-hour. The mosquito borne disease incidence peak was in July to August. A total of 37 cases of and 18 cases of were reported during 2010-2013. The highest adult mosquito density was in the livestock shed, which was 2.74 per light - hour among different environments. Conclusion The surveillance results of mosquito density and its seasonality provide guidance for urban mosquito control. The association of mosquito density with mosquito borne diseases should be analyzed to reflect the efficiency of mosquito control operations.