The gaseous phase PAHs in atmosphere and dissolved phase PAHs in water were sampled by high-volume air sampler and semipeameiable membrane device (SPMD) in Luhu Lake, respectively.According to the stagnant two-film model, the direction and magnitude of exchange fluxes of PAHs across air-water interface in Luhu Lake were calculated based on above data.The result showed that most PAHs were absorbed from atmosphere to water except naphthelene, acenaphthylene, and acenaphthene, which fluxes direction, was from water to atmosphere.Phenanthrene has highest magnitude of exchange flux(21211.22ng/(m²·d)), and then naphthelene, fluoranthene, anthracene, pyrene, fluorene et al.the largest exchange flux of PAHs was calculated for summer except for fluorene, which largest exchange flux was in winter.