Abstract: Composting technology, recognized as a pivotal method for the resourceful management of organic waste, has garnered significant attention due to its multifaceted benefits, including harmlessness, resourcefulness, and minimization. Despite these advantages, there are numerous problems in the composting process, especially the serious and vast amount of nitrogen loss, a critical nutrient. The incorporation of microbial agents has been identified as an effective strategy to mitigate this loss. The research delved into the various factors that influence the nitrogen content (total nitrogen content, carbon-nitrogen ratio, ammonium nitrogen, nitrate nitrogen) and loss (ammonia emission, total nitrogen loss) during the composting process, including the type and source of microbial agents, the dosage of inoculation, the composting materials, the composting methods, and the scale of production. The research found that adding inoculants could significantly enhance the total nitrogen (19.34%), ammonium nitrogen (40.77%), and nitrate nitrogen (2.30%) content, while reducing emission of ammonia (-14.91%), decreasing C/N (-37.87%) and the total nitrogen loss (-29.68%) at the same time. A critical discovery from this research was that the resource of the microbial inoculants played a decisive role in the preservation of nitrogen within the compost. Local inoculants, namely indigenous agents, selected and obtained from composting environment, have shown a remarkable ability to adapt and thrive in the same and complex environment. They were found to be the best for improving the total nitrogen content of the compost (16.9%), compared to other three types of inoculants, and were more favorable for nitrogen fixation and emission reduction in the composting process. Contrary to the common belief that higher quantities of microbial agents always yield better results, this research suggested a more nuanced approach. It was observed that the addition of microbial agents at a rate of less than 2% has the most pronounced effect on the total nitrogen content and C/N ratio of the composts. Interestingly, when the addition rate is less than 1%, it has the most significant impact on the increase in ammonium nitrogen content. Due to the fact that many published researches preferred using cellulose degrading microorganisms, the addition of inoculants accelerated the degradation of organic matter rather than nitrogen, resulting in the content of organic matter being much lower than the total nitrogen in the compost. In addition, with the increasing dose range of inoculants, the C/N ratio was significantly decreased. The research also highlighted the importance of considering the type of composting raw materials. Materials with an initially low C/N ratio, such as poultry and livestock manure, may not respond as effectively to the addition of microbial agents for nitrogen fixation as other materials, thus adding inoculants had less effect on improving the total nitrogen content of compost than other types of raw materials. Furthermore, the research identified reactor composting as an exceptional method for nitrogen fixation and loss reduction, and it was the best method for conserving nitrogen in compost compared to other processes, with the exception of traditional composting. Therefore, the strategic use of microbial agents in composting can significantly enhance the nitrogen content of the final product. The resource of the inoculant, especially local inoculants, had the best effect on nitrogen conservation, and the reactor was the best way for composting than pile and windrow process.