Abstract: In China’s agricultural production, a large amount of nitrogen fertilizer is used every year. Compared with the normal needs of crops, nitrogen fertilizer is often used in excess, which has a negative impact on the growth and development of crops, human health, and the environment. For this reason, this article reviews the effects of nitrogen fertilizer application on soil, crops, and environment, and summarizes the best application rate of nitrogen fertilizer, hoping to be helpful to the rational use of nitrogen fertilizer in our country.