【Abstract】 Objective To monitor the population density and seasonal fluctuation of mosquitoes in different areas in Hebei, and to provide the science basis for the reasonable control of mosquitoes. Methods Mosquitoes were collected by light trap method and landing count method. Results There were six species caught, belonging to 3 genera. Culex pipiens pallens was the dominant specie, accounting for 85.34%. Cx.pipiens pallens was caught in the residential areas and park, Cx.tritaeniorhynchus and Anopheles sinensis in stable. The mosquitoes density was monitored by light trap method and landing count method, and its peaks lasted from July to September, but the peak was in August. The mosquito density was 10.33 individuals/lamp·h and 16.06 individuals/man·h  respectively.  Conclusion It  should  put  the emphasis on the control of Cx.pipiens pallens, Aedes albopictus, Cx.tritaeniorhynchus and An.sinensis.