Using satellite remote sensing technology to observe sea surface wind fields has become an important instrument. The successful launch of Tiangong-2, the future Surface Water and Ocean Topography (SWOT) mission, and demonstrating GaoFen Project provides the future understanding for the generation of new wide-swath imaging altimeter. The constructed data sets and validated data sets of the model function were obtained by combining the observable conditions of imaging altimeter with the theoretical model of sea surface backscattering coefficient. A model function for wind speed retrieval at incidence angles from 1 deg to 7 deg and from 7 deg to 11 deg was proposed, which is suitable for wide-swath imaging altimeter, model coefficients were calculated using the constructed data sets, model functions were validated using the validated data sets. The validated results of model function show that the root-mean-squared error (RMSE) ranged from 0.005 to 0.72  m  /  s. Wind speed was retrieved with China France Oceanography Satellite (CFOSAT) Surface Waves Investigation and Monitoring instrument (SWIM) L2 data for incidence angles from 3 deg to 10 deg with 0.5 interval, and wind speed was validated with European Centre for Medium-Range Weather Forecasts (ECMWF) data. The results of wind speed validation show that the average of RMSE is 1.6  m  /  s. Therefore, the wind speed retrieval was validated with the wind speed from ECMWF, which showed good coincidence.