Abstract: In order to provide winter wheat yield assess for agriculture department, experimental fields of winter wheat yield data in May before harvest, and the synthetic aperture radar (SAR)double polarized: RDARSAT-2 that were photographed in April and May in Huaihe River Region were adopted for winter wheat yield estimating. Then yield estimating model was established using different fitting methods between winter yield and backscatter coefficient of 2 time phase. The other experimental fields were chosen to test estimating models. Finally, best estimating model was chosen to accomplish winter wheat yield estimating. The results showed that: exceeding 80% precision yield estimating model and yield estimating result were obtained. Using SAR for yield estimating about a month before harvest, it illustrated these ideas and methods were effective.