With the intensification of global climate change, carbon emission control has become an international consensus. As one of the urban carbon sources, urban wastewater treatment plants have seen their carbon emission issues during the operation stage become increasingly prominent. Accurate quantification of carbon emission levels at this stage is the foundation for the industry to achieve low-carbon transformation. Taking a certain wastewater treatment plant as a case study, this paper analyzes the emission laws and characteristics of greenhouse gases (GHG) during its operation process, identifies key emission sources in combination with process characteristics, and accordingly proposes targeted emission reduction strategies. The research results can provide theoretical and practical references for the accurate accounting of carbon emissions, optimization of low-carbon operation, and formulation of industry emission reduction paths in urban wastewater treatment plants.