At present, more and more urban sewage treatment plants are put into construction and operation in China. While improving the quality of the water environment, the urban sewage plant has brought new problems to its surrounding environment, the most typical of which is the problem of odor pollution. In this study, the urban sewage treatment plant is taken as the object to study the discharge rule of typical odorous substances, which provides theoretical guidance for the evaluation and control of odor pollution in the urban sewage treatment plant The results of studies on typical odorous substance discharge concentrations indicate that H${}_2$S is the main odorous pollutant in the wastewater treatment plant, and treatment units with higher odorous substance discharge concentrations include grids, aeration grit tanks, and mud storage tanks. The H${}_2$S emission concentration of the inlet pump house, grille and aeration grit tank is low in winter and high in summer, and will be significantly reduced during rainfall. The H${}_2$S discharge concentration of the inlet pump room, grille and aeration grit tank is significantly positively correlated with the sewage temperature.