Abstract: To accurately quantify carbon emissions throughout the cigarette manufacturing process and to identify section-specific emission reduction points, X cigarette factory was studied and a conventional direct-indirect classification method (algorithm A which calculated carbon emissions separately for cigarette making section, primary processing section, power department, logistics department and department of support services in the cigarette factory) was first used to analyze the major carbon emission source data trends, including electricity consumption, and purchased natural gas. A production-stage segmentation method (algorithm B) and a machinery-personnel integrated method (algorithm C which distributed the carbon emissions of the department of support services to each production section according to the proportion of personnel, and combined them with equipment emissions to calculate the total carbon emissions including personnel emissions of the sections and departments) were further proposed to improve section-level carbon calculation, and scenario analysis was then conducted to evaluate the emission reduction potential of the key factors in different sections. Results showed that: 1) Based on algorithm A, X cigarette factory emitted 1.72-2.27 tons of CO₂ from 2019 to 2021. Emission items in proportion descending order were electric power consumption (about 70%), fossil fuel combustion (about 25%), wastewater treatment (about 3%) and refrigerant consumption (<1%). 2) Based on algorithm B, carbon emissions from X cigarette factory in proportion descending order were cigarette making section (34% to 36%), power department (23% to 25%), primary processing section (24% to 25%), department of support services (10% to 14%) and logistics department (about 3%). 3) Compared with algorithm B, algorithm C further considered the carbon emissions caused by the various sections or equipment operators in their daily lives and work processes (such as natural gas consumption in the cafeteria), resulting in a 40% increase (an increase rate of 4-6 percentage points) in carbon emissions in the cigarette making section, and a slight increase in carbon emissions in the primary processing section and power department, with an increase rate of about 3 percentage points and 1 percentage point, respectively. 4) The scenario analysis results showed that when the overall energy consumption was reduced by 30%, the emission reduction potential of each section ranged from 0.2 to 4.3 kgCO₂ per 10 000 cigarettes. If the top 3 equipment in terms of carbon emission proportion in each section and department were automated and upgraded to reduce energy consumption by 30% and operators by 50%, the emission reduction potential of the section and department was 0.49-4.39 kgCO₂ per 10 000 cigarettes. This method provides reference for tobacco industry enterprises to carry out carbon emission management and formulate targeted emission reduction strategies.