Abstract: In order to study the changes of surface chemical structure of coal in three different CO production methods, including gas desorption, room temperature oxidation and high temperature oxidation, Fourier transform infrared spectrometer (FTIR) was used to detect the three different ranks of coal samples in nitrogen atmosphere for 72 h, oxidation condition at 25 ℃ for 72 h and 100 ℃ for 10 h. The results show that there is no chemical reaction in the process of non-oxidizing CO production. Under normal temperature and air condition, the low rank coal sample reacts with the oxygen in the air, and the surface functional group changes slightly, mainly decreases the content of aliphatic hydrocarbons, increases the oxygen-containing functional group at 1 379 cm^-1 to 1 373 cm^-1, and the change of high-metamorphic anthracite is not obvious. Under the air condition of 100 ℃, the reaction of low-metamorphic lignite is the most obvious and it is mainly due to the decrease of aliphatic hydrocarbons content and the difference of absorption peaks of benzene structure. The study highlights the intermediate characteristics of surface active groups of coal in the oxidation process before entering the combustion stage.