Exploring　new　methods　for　comprehensive　mining　of　coalbed　methane　(CBM)　is　a　research　hotspot.　Pore　connectivity　has　a　significant　impact　on　the　permeability　of　coal,　and　as　connectivity　increases,　it　has　a　positive　impact　on　the　desorption　and　seepage　of　CBM.　To　quantify　and　visualize　the　pore　development　of　coal　under　three　cyclic　treatments,　T2　and　T1-T2　spectra　obtained　by　nuclear　magnetic　resonance　(NMR)　and　Surface　roughness　obtained　by　atomic　force　microscope　(AFM)　were　selected　for　characterization.　The　NMR　results　indicate　that　microwave-assisted　cyclic　oxidation　can　stimulate　the　formation　of　pores　and　pore　throats　and　effectively　dissolve　the　coal　matrix,　thereby　changing　the　structure　of　the　coal,　manifested　by　a　growth　rate　of　−5.84　%　for　irreducible　porosity　and　31.5　%　for　producible　porosity.　Cyclic　oxidation　and　microwave　have　a　certain　impact　on　the　conversion　of　micropores　to　mesopores,　but　have　a　relatively　less　impact　on　the　evolution　of　new　pores.　The　maximum　Rq　and　Ra　obtained　by　AFM　of　microwave-assisted　cyclic　oxidation　are　84.7　nm　and　70.3　nm,　respectively.　Moreover,　its　Rsk　and　Rku　are　less　than　zero　and　three,　respectively.　This　indicates　that　microwave-assisted　cyclic　oxidation　has　the　best　effect　on　changing　the　internal　and　surface　morphology　of　coal.　©　2023　Elsevier　Ltd