Under field conditions,changes of grain filling and yield of winter wheat with large-ear cultivar Yumai66 were studied in Zhengzhou experimental sit in Henan province during the 200~2002 growing seasons,there was different significantly between 2000~2001 and 2001~2002.The grain filling process of Yumai66,were modeled with Cubic,Quadratic and Logistic equation,R~2 values of modeled equations were significant,and the Cubic R~2 value was the significantest.There was a significant correlation between W and Ws,Se,S in dry year of 2000~2001,and between W and Ws,V,Vs,Vmax in rainy year of 2001~2002.In comparison with 2001~2002,grain filling duration was shortened,filling rate was smaller,which resulted in falling of grain weight in 2000~2001.Effects of irrigation on filling parameters were different between two year-styles,with irrigation improving,S and Se was lagged,filling rate reduced in 2000~2001,but S and Se was shortened,grain filling rate of irrigation treatment with one application was lowest,that of irrigation treatment with two applications was the highest in 2001~2002.Irrigation improved yield significantly in 2000~2001,but there was not significant different between treatments,even yield of irrigation treatment with three applications was lower than that of irrigation treatment with two applications in 2001~2002.