Accurate estimation of regional winter wheat yields is of great significance for understanding the agricultural production status and ensuring national food security. Light use efficiency (LUE) model is one of the most used models for crop yield estimation, however an important parameter, maximum light use efficiency (ξ_max), still remains large uncertainties, and whether the crop ξ_max changes along with time is also to be explored. In this paper, Savitzky-Golay (S-G) method is used to filter the time-series moderate resolution imaging spectroradiometer (MODIS) vegetation indices data, and a quadratic difference method and a spectral mutation method are used to extract the winter wheat planted areas during 2000—2015 in Shandong Province. Then a fixed ξ_max and a changed ξ_max are used to drive the CASA (the Carnegie-Ames-Stanford approach) model for years from 2000 to 2016 respectively. Using harvest index (HI) and winter wheat planted areas, the winter wheat yield during 2000—2016 in Shandong Province are obtained, to explore the effect of ξ_max on estimating winter wheat yield. The results show that the filtered time-series vegetation indices data capture the spectral features of winter wheat during the growth stages, and the extracted method used in this paper shows a good universal property. The extracted winter wheat planted areas agree well with the planted areas from statistical yearbooks at the city level, and the determination coefficient (R²) between those reaches 0.71, which indicates the extracted winter wheat planted areas are reliable in this paper. The R² between statistical yields and yields estimated with a changed ξ_max is 0.32, which is higher than that between statistical yields and yields estimated with a fixed ξ_max. This indicates that the ξ_max of winter wheat is changed along with time, and the varieties replacement of winter wheat may be responsible for this. Both the statistical and estimated yields of winter wheat during 2000—2016 show increasing trends with increasing rates of 93.12 and 149.79 kg·hm^-2·a^-1, respectively. The winter wheat yields in the western Shandong province are overall higher than those in the eastern study area.