Abstract: Based on the updated operational estimates of reference evapotranspiration by Penman-Monteith the relative evapotranspiration in various development stages of winter wheatin North China were calculated.The results sho w thatthe proposed dro ughtindexes have agricultural meaning,the analysis and assessments well fit to facts.The agricultural drought impact assessmentusing integrated model in consideration of winter cold status and water condition in various stages of winter wheat got good results.