Stannous chloride (SnCl2) was firstly used as an inhibitor to prevent coal oxidation. Thermal analysis was used to study the influence of SnCl2. Weight increase due to oxygen chemisorption, the ignition temperature, the burnout temperature and heat released during the whole process were evaluated as main parameters. The results indicated that the addition of SnCl2 leads to significant reduction in the percentage of mass increase. The presence of SnCl2 caused increase in the ignition temperature and decrease in the heat released. However, there is probably no effect of SnCl2 on the burnout temperature. The mechanism of the SnCl2 suggested that the addition of SnCl2 to the coal oxidation mainly influence the oxygen chemisorption by consuming more oxygen. Thus, SnCl2 can be recommended as effective inhibitor to coal oxidation.