The radar backscattering from the ocean surface results mainly from the Bragg scattering caused by the short gravity waves

which are related to wind vector

boundary layer phenomena

etc. Hence

it is reasonable to retrieve the wind field information from the radar cross section of the ocean surface. Much work has been done on deriving the ocean spectra from SAR imagery and wind speed from radar cross section. In this paper

the （SIR C）/（X SAR） data acquired in April

1994 are analyzed over the South China Sea. Firstly

the SAR image spectra are calculated

and the wind direction is estimated. The wind speed is derived using the sigma naught of the C band data with the CMOD4 model. The results are validated with the composite model. It is shown that SAR is one of useful tools for the retrieval of comprehensive wind information over the ocean.