Abstract: Due to the influence of geometric factors, when using the spaceborne GNSS-R to retrieve the sea surface wind speed, the cross-section of the double-base radar obtained cannot be used directly to retrieve the wind speed. The influence of geometric factors on wind speed inversion is studied on the basis of analyzing the characteristics of GNSS sea surface reflection signals. After correcting the cross-sectional area and effective scattering area of the double-base radar, the reflected signal power of the corresponding reflection point is obtained. Finally, these obtained reflection signal parameters are verified by simulation.. The experimental results show that the root mean square error of sea surface wind speed inversion is 2.61 m／s, and the correlation between the inversion wind speed and the real wind speed is 0.75. The normalized double-base radar scattering power after correction can effectively retrieve the sea surface wind speed.