Abstract: To accurately quantify carbon emissions throughout the cigarette making process and to identify section-specific emission reduction points, X cigarette factory was studied and a conventional direct-indirect classification method (algorithm A) was first used to analyze the major carbon emission source data trends, including electricity consumption, and purchased natural gas. A production segmentation method (algorithm B calculating carbon emissions separately for cigarette making section, primary processing section, power department, logistics department and department of support services which included administrators and operators from all production sections in the cigarette factory) 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 emission 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 17, 200 - 22, 700 tons of CO₂ per year 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% - 36%), primary processing section (24%- 26%), power department (23%-25%), department of support services (10%- 14%) and logistics department (about 3%). The units with the highest carbon intensities in each section or production line were the heat exchange system in auxiliary production room, refrigerator, air conditioner, general system for logistics, and dining hall. 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 dining hall), resulting in a carbon emission proportion of over 40% (an increase rate of about 6 percentage points) for the cigarette making section, and a slight increase in the carbon emission for the primary processing section, with an increase rate of about 2 percentage points. 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 0.22 to 4.33 kgCO₂ per 10, 000 cigarettes. If the top three 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.