Food consumption is an important process of urban nutrient metabolism. By taking Xiamen city for example, the changes of food nitrogen consumption during 1988-2009 years were analyzed. Then the associated economic and social driving factors and its environmental loading were researched. The results showed that changes of per capita food nitrogen consumption of Xiamen residents were not exactly the same with changes of per capita food consumption. Per capita nitrogen consumption maintained in 3.29 kg before the year 2000.However,there was a fluctuant growth after 2000, and per capita food nitrogen consumption reached a high value of 4.00 kg in 2004. The total food nitrogen consumption in Xiamen has grown rapidly, from 5400×10³ t in 1988 to 15000×10³t in 2009. Meanwhile, the proportion of grain in the food nitrogen consumption decreased from 45.5% to 15.9%. On the contrary, poultry meat and dairy products increased from 25.0% and 0.4% to 29.8% and 8.8%, respectively. In addition, correlation analysis was adopted to find that the positive correlation existed between the per capita disposable incomes, food price index, proportion of population with college degree and per capita food nitrogen consumption. Meanwhile, there was a negative correlation between the Engel's coefficient, the average number of family members, and per capita food nitrogen consumption. Selecting the year of 1988, 1994, 2001 and 2008 to analyze the environmental loading of food nitrogen consumption, it was found that the environmental nitrogen loading increased from 3509.12 t in 1998 to 7629.36 t in 2008, and more than 90% of nitrogen came to the soil and water. During 1988 to 2008, the proportion of nitrogen which entered to the soil increased from 37% to 60%. Meanwhile, the proportion of nitrogen to the water reduced from 57% to 35%.