Coalbed　methane　is　a　clean　energy　source　that　helps　reduce　greenhouse　gas　emissions.　Its　low　permeability　poses　great　challenges　to　low-cost　mining　and　impacts　the　economic　benefits　of　its　development　and　utilization.　High　Temperature　Steam-Liquid　Nitrogen　Cyclic　Treatment　(HLCT)　presents　a　novel,　environmentally　benign,　and　efficacious　technology,　which　promotes　the　iteration　of　pores　in　coal　through　repeated　hot　and　cold　cycles.　This　article　used　hydrogen　nuclear　magnetic　resonance　to　characterize　the　change　of　coal　after　HLCT　at　the　microscopic　level.　The　evolution　trend　of　internal　pores　was　analyzed　based　on　the　T2　spectrum,　and　the　T1-T2　spectrum　was　plotted　to　show　the　distribution　of　fluids.　Nuclear　magnetic　characteristic　parameter　variation　was　examined,　and　the　trends　of　Ds　and　De　before　and　after　cyclic　processing　were　explored.　The　results　indicate　that　as　the　cycle　progresses,　the　number　of　pores　at　different　scales　in　the　coal　increases,　the　free　fluid　storage　space　expands,　Specifically,　after　15　cycles,　permeability　improved　by　1621.72%,　and　porosity　increased　to　29.05%.　The　Ds　of　coal　decreases　with　cycles　while　De　is　the　opposite.　This　study　highlights　the　potential　of　HLCT　in　coalbed　methane　extraction　while　providing　valuable　insights　for　optimizing　coal　resource　utilization　in　alignment　with　clean　energy　goals.　©　2024　Author(s).