The influence of igneous intrusion on entire coal oxidation and its mechanism remains unclear, impacting mining operations. To investigate spontaneous combustion characteristics, this study analyzed the composition and physicochemical structure of igneous intrusion coal (II coal) using various experimental methods: low-temperature oxidation, low-pressure N2 adsorption, XPS, FTIR, and TGA-DSC. Results show that II coal has developed pores favourable for coal-oxygen interaction, but increased moisture and ash relative content, and decreased volatile and reactive functional groups, implying reduced low-temperature oxidation and combustion reactivity. The decrease in CO and CO2 production and the increase in XPT and apparent activation energy confirm this result. Notably, II coal releases more CO and CO2 below 400 K and the gases are lower than raw coal after 400 K, suggesting native CO and CO2 exist in coal and abundant native active sites which are rapidly consumed during this stage. These findings provide insights into predicting spontaneous combustion in mines extracting coal seams affected by igneous intrusion.