The northern Guizhou area boasts abundant shale gas resources. The main target layers are two sets of organic- rich source rocks in the Niutitang and Longmaxi formations, which possess a substantial hydrocarbon- generating material basis and potential. However, the nitrogen content in the rock reservoirs generally exceeds 80%, while the methane content remains low. In response to this phenomenon, shale gas composition and C/N isotope tests were carried out, and the sources of CH4, CO2, and N2 in shale gas wells were analyzed. Combined with shale geochemical characteristics, regional tectonic evolution background, core fracture distribution, deep magmatic hydrothermal activities, and the anatomy of typical shale gas wells, the nitrogen enrichment mechanism of shale gas wells in the Niutitang Formation of northern Guizhou was discussed. Our findings revealed the complexity of the regional geological structure in northern Guizhou, where the reservoirs have been significantly affected by multi- stage tectonic movements, resulting in the development of faults and fractures.Furthermore, the fractures in the shale core of the Niutitang Formation are mostly filled with calcite, indicating frequent magmatic hydrothermal activities in the area. Additionally, the gas content of shale varies noticeably across different structural belts, with a recurring regional pattern of high nitrogen content and low methane content. Moreover, our research classified CH4 in shale gas as a thermal cracking gas of organic origin, while CO2 is formed during the thermal transformation of organic matter. The source of N2 is related to the thermal ammonification of organic matter and the inflow of magmatic hydrothermal fluids from the deep crust and upper mantle along faults, particularly during the mature (especially highly mature) stage. Considering the relatively stable structure, undeveloped fault fractures, and infrequent magmatic hydrothermal activities, the paleo- uplift area is the preferred direction for shale gas development.The insights gained from this research can provide valuable theoretical guidance for understanding the accumulation mechanism of shale gas in the Niutitang Formation, as well asinform subsequent resource evaluation and exploration deployment.