Abstract: Wind-induced sea surface roughness is the main error source for microwave radiometer to receive brightness temperature.Based on SMAP satellite L2C sea surface brightness temperature data and 10 meters wind speed data, analyzes the gain the correlation between wind speed and brightness temperature, and by using least square method based on rough sea surface under different wind speed range build L-band gain brightness temperature model, considering the influence of whitecaps on brightness temperature, input Argo buoy interpolation temperature and salinity data sets, and use Meissner -Wentz dielectric constant temperature model to calculate the reference brightness temperature. Regression analysis is carried out with the flat sea surface brightness temperature corrected by the brightness temperature gain model, and the applicability of the model in the sea area was quantitatively evaluated. The results show that there is a positive correlation between wind speed and brightness temperature gain. The brightness temperature sensitivity of horizontal polarization in the wind speed range of 0～3 m/s is 0.25 K higher than that of vertical polarization mode, the former is 0.02 K higher than the latter in the wind speed range of 3～12 m/s, and the former is 0.01 K higher than later when the wind speed is greater than 12 m/s; In the sea surface brightness temperature deviation near the land area is relatively large, and in the open sea most polarization brightness temperature errors can be controlled within 0.2 K.The determination coefficients of the regression analysis of the model and reference brightness temperature are both above 0.5, and the root-mean-square error can be controlled within 0.2 K.