A field experiment was carried out in two main paddy soils (Wushan soil,Huangni soil) in Taihu Area to study nitrogen uptake and utilization by rice,effect of nitrogen fertilizer on rice yield,and economic efficiency of N fertilization.The results indicated that the nitrogen uptake rate of rice was the highest at the booting stage,being around N 2.2~4.2 kg/(hm²·d),and the nitrogen apparent utilization rate of rice was about 31.62%~46.15%,and 37.64% on average.The recommended optimal N application rate was about N 227 kg/hm² in Huangni soil and 255 kg/hm² in Wushan soil for rice production.