Abstract: In order to study the effect of igneous rock intrusion on coal oxidation, the electronic scanning mirror, specific surface area tester and pressure mercury meter are used to test the coal samples before and after the igneous rock intrusion, by comparing and analyzing the scanning electron microscope, specific surface area and pore volume of coal samples before and after igneous rock intrusion, the changes of microstructure and porosity of coal samples before and after igneous rock intrusion are studied. The results show that the pore structure of the coal sample changes after the igneous rock intrusion, the porosity increases, and the oxygen adsorption ability is enhanced; the change of coal molecular structure leads to the oxidation of metamorphic coal after igneous rock intrusion, and the greater the metamorphic degree, the easier the oxidation.