Abstract: A coal-based synthesis natural gas (SNG) project was planned to set up near the Baganuur coal mine in Mongolia. To mitigate carbon dioxide (CO₂) emissions and promote the sustainable development of coal conversion projects, a pre-feasibility study of full-chain carbon dioxide capture, utilization and storage (CCUS) retrofitting to the SNG project was assessed. Based on the characteristics of the SNG project and the geological setting of Mongolia, a feasibility study framework was used to assess the potential CCUS project. The feasibility study framework includes evaluation and selection of storage sites, site performance evaluation, project design of full-chain CCUS, techno-economic evaluation, etc. Results showed that there are sufficient high suitability and a huge capacity for CO₂ aquifer storage in most parts of the Nyalga basin, and the selected site is with low geological risks. The technical scheme of full- chain CCUS is that high purity CO₂ from industrial separation can be directly compressed and transported to the suitable geological sites nearby by onshore pipeline. It assumed that 90% of the total CO₂ capture is used for enhancing the recovery of water (CO₂-EWR) and 10% is for sale to oil companies for enhancing the recovery of oil (CO₂-EOR) projects or other utilizations. The project can annually reduce CO₂ emissions of 5Mt and produce saline water of 5.13 Mt with a levelized cost of 18.8 USD/t. This study shows that the full-chain CCUS project accompanied by the SNG factory is applicable and low-cost. It is a sign for the low-carbon and sustainable development of fossil-based industries in the Mongolia and other countries of one Belt and one Road region.