Under the field conditions,effects of nitrogen applying stages on grain filling were studied using winter wheat cultivar ‘Aikang58’ as materials.The results indicated that the process of grain weight increase presented "S" shape during the course of wheat grain filling.Grain weight and dry weight were an increasing trend in the process of grain filling;grain volume increased at first and then decreased.Effects of nitrogen applying stages on grain filling are different,the highest grain dry matter accumulation and grain filling rate of ‘Aikang58’ were observed in N3 treatment.