Abstract: An experimental system for Ka-band sea clutter measurement is introduced in this paper. Based on the measured data, the sea clutter characteristics are analyzed. It is found that the amplitude distribution of sea clutter data is close to the Rayleigh, Weibull and K distributions and it has slight differences in horizontal and vertical polarization when the grazing angle is low. The temporal correlation of sea clutter is very short and almost the same in different polarization modes. The spatial correlation length is about 4 m and increases slightly with the increase of grazing angle. In addition, the trend of the backscattering coefficient of sea clutter under the two polarizations of HH and VV is compared and analyzed. The results show that the backscattering coefficient of sea clutter under VV polarization is higher than that under HH polarization, which provides support for low-altitude small target detection concerning the sea clutter.