Based on the observational data at Zhanjiang from 31 March to 2 April 2010,microphysical characteristics and evolution of aerosol particle size distribution for a sea fog which was influenced by cold front were analyzed.The results showed that the formation and dissipation of sea fogs was closely related to wind field.The formation and development of sea fogs usually occurred in east southeast wind,while weak northeast wind was the main factor to dissipate the persistent sea fog.The variation range of fog droplet number concentration and liquid water content were 10⁰—10² cm^-3 and 0.001—0.232 g·m^-3,respectively.The mean radius was less than 10 μm and the peak radius was mostly near 1.4 μm.The fog droplet size distribution of the sea fog events was mainly of a monotonically decreasing type with the spectrum width larger than 20 μm.The fog droplet spectrum width presented abrupt broadening and rapid reducing phases during the sea fog events whereas the change in fog droplet number concentration was mainly caused by the number density variation of fog droplets with radiuses of less than 5 μm.Sea fogs exerted insignificant wet scavenging effect on aerosols.The number density of aerosol particles with diameters of less than 0.1 μm or more than 4 μm decreased dramatically during sea fogs,but quickly returned to their normal levels before the formation of sea fogs.