The continuous increase of global nitrogen fertilizer use has led to the increasingly serious problem of N2O emissions. How to effectively reduce N2O emissions and improve nitrogen use efficiency has become the focus of research. Dissolved organic matter (DOM) plays a crucial role in the soil nitrogen cycle, directly or indirectly influencing processes such as nitrogen mineralization, immobilization, nitrification, denitrification, and N?O emissions. Therefore, this review aims to deeply analyze the regulatory role of DOM in soil nitrogen cycle and N2O emissions, mainly involving the following aspects: (1) By providing a carbon source and energy, DOM promotes microbial metabolic activity, accelerating the mineralization of organic nitrogen and alleviating nitrogen supply limitations; (2) The composition and form of DOM significantly regulate nitrogen immobilization, nitrification, and denitrification reactions, affecting the rate of nitrogen transformation in the soil; (3) During nitrification and denitrification processes, DOM can act as an electron donor and influence nitrogen transformation by altering the soil microbial community structure. Understanding the impact of DOM on the soil nitrogen cycle not only helps to comprehend the dynamic changes in soil nitrogen but also provides a theoretical basis for mitigating greenhouse gas emissions and optimizing agricultural management.