In order to carry out the process accounting analysis of carbon emission of mining enterprises and help the low-carbon construction of mines, Chengchao Mining is taken as a typical iron mine case in China, on-site data of energy and equipment is collected through research, and equipment demand/utilization coefficient is introduced to establish the connection between rated power and actual power to the accounting process based on the carbon accounting industry guidelines for mining enterprises, and the actual operation time of single equipment is investigated to estimate the electricity consumption of each system, and the carbon emission factor method is used to calculate the carbon emission; in this way, the carbon emission of mining, beneficiation, pelletizing processes and their subsystems can be analyzed and compared. The results show that, in 2021, the carbon emission of Chengchao Mining are about 179 604.15 t, the emissions per ton of iron concentrate are about 0.057 t CO₂, the emissions per ton of pellets are about 0.096 t CO₂, and the emission of pellet process are about 115 096.28 t CO₂, accounting for 64.08% of the total emissions. From the perspective of emission sources, the purchase of electricity is the main source of carbon emission, accounting for 52.51%, followed by carbon emission generated by fuel burn, accounting for 44.77%, and a small amount of carbon emissions caused by carbonate decomposition. From the perspective of process subsystem, the carbon emission of the lifting and coarse crushing system in the mining process is the largest, accounting for 37.30% of the emission of the mining process, the carbon emission of the grinding system in the mineral processing process is the largest, accounting for 46.90% of the emission of the beneficiation process, and the carbon emission of the roasting and cooling system in the pellet process is the largest, accounting for 75.80% of the emissions of the pellets process.