Abstract: Natural coke is a kind of fossil fuel with heating value of about 18—28 MJ·kg-1. There are abundant natural coke reserves in the world, but at present it is abandoned and research and development are needed for its utilization. Thermogravimetric analysis(TG) and Fourier-transform infrared(FT-IR) coupled technology was used to investigate the pyrolysis characteristics of natural coke (Peicheng mine, Xuzhou, Jiangsu Province, China) and bituminous coal (Hanqiao mine, Xuzhou, Jiangsu Province, China) in this paper. The pyrolysis products were analyzed with the VECTOR 22 infrared analyzer. The effects of heating rate, final pyrolysis temperature, particle diameter, and operating pressure on the pyrolysis process of natural coke were examined with the Thermax 500 pressurized thermogravimetry. The results showed that different from the pyrolysis of coal, including three stages—drying, semi-char forming and degasification,the pyrolysis process of natural coke could be divided into two different stages of degasification. With the increase of heating rate, the TG curve shifted to the high temperature area. The heating rate had almost no effect on the ultimate release of volatile matter. Final pyrolysis temperature had a strong impact on the ultimate release of volatile matter. The higher the final pyrolysis temperature, the more the ultimate release of volatile matter. SEM pictures showed that natural coke pyrolyzed at a higher temperature had a better porous structure, which was beneficial to the release of volatile matter and had a better reduction activity. Decrease in particle size led to more release of volatile matter. Pressure has less effect on pyrolysis at a lower temperature, while its effect became stronger when the temperature was higher than a given value.