Mesoscale eddies (10–500km) are important phenomena in the ocean which were discovered only in the 1960's. Because a vigorous circulation was associated with them, which are intimately related to the transport of variables like heat, salinity and momentum, they have been studied by the oceanographers for decades. In this paper, the electromagnetic scattering characteristics of sea surface were studied by using the approximate method. Combined with the wave-current interaction mode of sea surface, the current fields of mesoscale eddies were calculated based on the altimetry data. The spectrum perturbation in the current fields of mesoscale eddies were deduced, and finally...