A volume-surface composite model of rough sea surfaces with water bubble layer driven by wind is presented in this paper. Based on the modified two-scale rough surface scattering theory, MIE theory and VRT （vector radiative transfer） theory, the difference of electromagnetic scattering properties of the water bubbles compared with those of water particles is investigated. The relations between the foam coverage of the sea surface and wind speed and air-sea temperature difference are analyzed. The dependence of back- and bistatic-scattering coefficient of Gaussian rough surface and empirical sea surface with/without foam layer on the incident and azimuthal angle, the wind speed, the wind direction, as well as the polarization are discussed in detail. The results of numerical simulations are analyzed and compared with the measured data from the relevant references.