From the viewpoint of efficient fertilization, a field experiment was conducted to investigate the effects of nitrogen (N) application rates on dry matter accumulation and nutrient absorption of cassava and the contents of soil available nutrients. The results showed that the dry matter accumulation of stems and leaves increased significantly with the increase of N application rates, while the yield of root tubers increased with N application rates firstly, reached the maximum value at N 130 kg/hm² and then decreased with the further increase in N application rates. The maximum yield of cassava was increased by 18.13% compared to control with no nitrogen fertilizer applied. The increase in N application rates led to the accumulation of phosphorus and potassium in cassava organs and nitrogen accumulation in stems and leaves of cassava. However, nitrogen accumulation in root tubers increased firstly, reached the maximum value and then decreased with the further increase in N application rates. The agronomic and physiological use efficiency and partial factor productivity of applied nitrogen decreased significantly with the increase in N application rates. Nitrogen recovery efficiency reached the maximal value at 130 kg/hm², and was increased by 11.37% to 25.12% compared with other treatments. After cassava harvest, the alkali-hydrolyzed nitrogen content increased obviously with increasing nitrogen application, but available phosphorus and potassium contents decreased. The available phosphorus and potassium nutrients in the soil of all treatments, as well as the available nitrogen in the soil of the treatment with N 195 kg/hm² were obviously surplus. In conclusion, the optimum application amount of nitrogen for cassava was 130 kg/hm².