Abstract: In order to confront the severe eutrophication of Taihu Lake and radically reduce non-point source pollution, based on material flow analysis and the principle of mass conservation, we studied the nitrogen flow flux, efficiency and environmental load of the “crop-livestock breeding” system in Xinzhuang Town and regulated the parameters using the measured values. From 2000 to 2012, nitrogen flow flux of the crop production subsystem in Xinzhuang Town showed a declining trend, while the nitrogen flow flux of the livestock breeding subsystem represented a continuous wave between 42.5 and 50.9 kg/hm². Both nitrogen use efficiency and recycling rate were low; moreover, the rate of nitrogen loss to the environment was high. The percent of nitrogen loss into the surrounding water was 54.5% in the system. Since 2000, the proportions of the crop production and livestock breeding contributing to the environmental nitrogen load were 38.8%-50.2% and 25.4%-35.8%, respectively. The amount of nitrogen used in farmland and excreted by livestock was 310.8 kg/hm² and 61.1 kg/hm², respectively, which were well above the average values at the national scale (197.2 and 18.6 kg/hm²). Excessive use of chemical fertilizer and massive emissions of livestock excreta were the main reasons for aggravated environmental nitrogen load in the region. The “high input-high yield” mode of the agricultural production in Xinzhuang Town significantly enhances the difficulty of water environment restoration in Taihu Lake. Suggestions were proposed to relieve the environmental load of nitrogen, such as regulating the structure of crop and livestock production, promoting scientific fertilization and ecological breeding, combining crop production with livestock breeding to form industrial chain, and so on.