Abstract:China is the largest nitrogen (N) fertilizer-consuming country in the world, accounting for about 33% of world total. The overuse of N fertilizer has resulted in a cascade of environmental problems without a continuous increase in crop yield. This paper briefed the N budget and N use efficiency in the cropland of China from 1980 to 2010, analyzed various N losses and their associated environmental impacts with a special focus on the discussion about how to achieve the dual goal of food security and environmental sustainability by implementing knowledge-based N management practices.