Microwave　irradiation　has　become　a　potential　technical　method　for　coalbed　degassing,　which　can　effectively　improve　its　permeability.　A　coupled　electromagnetic-thermomechanical　damage　(ETMD)　model　was　established　to　study　the　damage　characteristics　of　coal　containing　pyrites.　Under　microwave　irradiation,　the　temperature　increase　rate　of　pyrite　was　significantly　higher　compared　to　the　coal　matrix.　The　coal　matrix　was　cracked　by　expansion　stress　in　high-temperature　spots.　In　the　rotational　heating　mode,　the　coal　matrix　was　easier　to　damage　than　under　the　static　heating　mode.　The　coal　matrix　damage　efficiency　was　also　related　to　the　position　of　the　sample　under　the　static　heating　mode.　Uniform　centripetal　pressure　could　inhibit　coal　matrix　damage.　Moreover,　the　pressure　distribution　affected　the　damage　paths.　Compared　to　no　confining　pressure,　the　percentage　of　areas　damaged　in　coal　was　lower　under　low　parallel　pressure　and　higher　under　high　parallel　pressure.