Based on the in situ data of five cruises, aerosol optical properties over the East China Seas are analyzed, and the SeaDAS aerosol models are also evaluated. Results show that about 60% of aerosols in these regions show weak absorption, 20% are strong scattering aerosols, and the rest 20% show strong absorption. Aerosol volume size distributions in these regions mainly have two peaks, but there is another inconspicuous peak between the coarse mode and fine mode. So it’s better to describe the volume size distribution by a sum of three lognormal distributions than by two. The comparison between the in situ data and the SeaDAS aerosol models indicates that the influence of strong absorbing aerosols such as dust and soot can not be ignored. The current SeaDAS aerosol models are mainly designed for non-absorbing or weak-absorbing aerosols, and can not entirely meet the requirements of atmospheric correction of ocean color remote sensing in the East China Seas.