"Fuji" apple trees were as the materials.Biomass,nitrogen content and accumulation in different parts of apple trees were studied in this paper.The results showed that biomass of tree and tree crown changed slowly from Mar 26 to Apr 30;and increased quickly after Apr 30.But biomass of roots system had no change from Mar 26 to Jul 30,and increased quickly after Jul 30.Nitrogen content in new organs(fruits,leaves and shoots) during early spring was higher than that in other time.The curve of nitrogen content in old organs(branch,trunk and root) assumed "V".From Mar 26 to Apr 30,nitrogen accumulation of tree increased slowly,kept stabilization during Apr 30 to Jul 30,and increased clearly after Jul 30.Nitrogen accumulation in different organs of apple tree changed largely in different time.And nitrogen accumulation in tree crown was higher than that in roots system any time.