<p>Nitrogen metabolism plays a key role in maintaining normal physiological functions of the organism and cell proliferation and differentiation. Nitrogen metabolism in normal human body maintains a dynamic balance to meet the body’s demand for synthesis of biological macromolecules such as proteins and nucleic acids. However, in the process of tumor development, the nitrogen metabolism of tumor cells is reprogrammed to meet the demand of rapid proliferation, showing significantly different metabolic characteristics from normal cells. Key enzymes in the tumor microenvironment affect nitrogen metabolism through multiple mechanisms, providing essential nitrogen sources and energy for tumor cells. In-depth exploration of the regulatory mechanisms of tumor nitrogen metabolism not only helps to reveal the molecular basis of tumor development, but also provides a theoretical basis for the development of new tumor therapeutic strategies. In this paper, the relationship between nitrogen metabolism and tumors is systematically elaborated from the characteristics of nitrogen metabolism in normal people, the reprogramming of nitrogen metabolism in tumor patients, the influence of key enzymes on nitrogen metabolism in the tumor microenvironment, as well as the mechanism of tumor nitrogen metabolism regulation, etc., so as to provide references for the related research.</p>