Abstract <p>In the context of comprehensive utilization of energy-saving and carbon-reducing solid waste, the preparation of catalysts from municipal sludge-based biochar is also one of the novel paths for sustainable utilization of resources. Based on the field operation data of the municipal sludge pyrolysis and carbonization project, this study established the full life cycle inventory of multi-energy flow and material flow data. Using SimaPro evaluation software and the economic analysis approach, from the perspectives of life cycle assessment, carbon emissions, and economic analysis, the effects of five preparation schemes in the production process on the environmental sustainability and techno-economic feasibility of catalysts prepared from the activation, impregnation, and roasting of municipal sludge-based biochar were examined. The results demonstrate that the global warming potential, human toxicity potential, and acidification potential are the main environmental impact indicators in the preparation process. Under the working condition of 1 t/h preparation capacity, the total carbon emission is lowest at 888.07&#xa0;kg CO₂ eq and highest at 2728.02&#xa0;kg CO₂ eq. The variation range of total carbon emissions reached 67.45%. The variation range of the benefit–cost ratio reached 70.66%, gross profit margin reached 35.46%, and net present value reached 41.59%. The preparation process of municipal sludge biochar-based catalysts selects the scheme with a reasonable output structure and can reduce the overall environmental burden and promote the circular economy of pyrolysis and carbonization products, which is a good strategy for energy saving and emission reduction of organic solid waste resource utilization.</p> Graphical Abstract <p></p>