The continuous increase of globally using nitrogen fertilizer has led to a growing concern over N?O emissions.How to effectively reduce N₂O emissions and improve nitrogen use efficiency has become the key points of current studies.Dissolved organic matter （DOM） in soil plays a crucial role in the nitrogen cycling in soil，directly or indirectly affecting process of the mineralization，immobilization，nitrification，denitrification of nitrogen and the N?O emissions.This article reviewed the regulatory role and mechanism of DOM in the nitrogen cycling and N₂O emissions in soil mainly from the following aspects including DOM promoting the metabolic activity of microorganisms in soil by providing carbon sources and energy，thereby accelerating the mineralization of organic nitrogen and alleviating the limitations of nitrogen supply，the composition and morphology of DOM significantly regulating the fixation，nitrification，denitrification of nitrogen and affecting the transformation rate of nitrogen in soil，and DOM serving as an electron donor during the nitrification and denitrification of nitrogen and affecting the transformation of nitrogen by altering the structure of microbial community in soil.Analyzing the effects of DOM on nitrogen cycling in soil both helps to understand the dynamic changes of nitrogen in soil and provides a theoretical basis for mitigating the emissions of greenhouse gas and optimizing the management of agriculture.