Abstract:The fast development of urbanization in China may bring huge ecological pressure and serious environmentally pollution. This article studied the nitrogen fluxes in food consumption systems of households of rural and urban inhabitants of China in 1982 1992 and 2002 and explored the influence of urbanization on nitrogen emission into water. The results showed that the amount of excreled urine nitrogen and the emission of nitrogen into water was higher for urban inhabitants than that for rural inhabitants.The nitrogen emission into water per capita of urban inhabitants was about the same as that of rural inhabitants in 1982. However the nitrogen into water per capita of urban inhabitants was 2.8 times of that of rural inhabitants in 1992 and 2002. The emission of urine nitrogen into water was about equal for urban and rural inhabitants in 1982. The emission of urine nitrogen into water of urban inhabitants increased up to 56.7% by 2002;the emission of urban inhabitants was 34% lower. The scenario analysis showed that the emission of urine nitrogen into water increases up to 121-155 ten thousand tons in 2020,if the protein consumption increases because of a increasing population.Improving the use of urine nitrogen and sewage handling can reduce the emission of nitrogen into water.