As　the　power　density　of　press-pack　insulated　gate　bipolar　transistor　(PP-IGBT)　modules　increases,　establishing　a　thermal　analysis　model　to　provide　thermodynamic　information　for　PP-IGBT　modules　under　service　conditions　is　crucial　for　reliability　design　and　thermal　management.　Existing　thermal　models,　such　as　one-dimensional　(1D)　lumped　RC　thermal　network　models,　have　limitations　in　terms　of　accurately　predicting　the　thermal　behavior　of　PP-IGBT　modules;　i.e.,　the　effect　of　thermal　contact　resistance　degradation　resulting　from　contact　surface　damage　on　the　junction　temperature　is　not　considered.　This　study　proposes　an　improved　1D　lumped　RC　thermal　network　model　for　PP-IGBT　modules.　Following　different　numbers　of　power　cycles,　the　transient　PP-IGBT　module　thermal　impedances　were　measured,　and　the　evolution　of　the　thermal　contact　resistances　at　each　contact　surface　was　obtained.　Then,　thermal　contact　resistance　degradation　was　introduced　into　the　RC　thermal　network　model.　We　compared　the　calculated　junction　temperature　results　with　the　measured　results　to　verify　the　proposed　model.　The　model　enables　a　more　accurate　prediction　of　the　junction　temperature　of　PP-IGBT　modules　under　long-term　service　conditions.　IEEE