As　a　new　type　of　functional　material,　porous　graphite　foam　exhibits　unique　thermal　physical　properties　and　geometric　characteristics　in　heat　transfer　applications.　It　has　the　advantages　of　low　density,　high　specific　surface　area,　high　porosity　and　high　bulk　thermal　conductivity,　which　can　be　used　as　the　core　component　of　small,　lightweight,　compact　and　efficient　heat　sinks.　Effective　thermal　conductivity　serves　one　of　the　key　thermophysical　properties　for　foam-cored　heat　sinks.　The　complex　three-dimensional　topology　and　interstitial　fluids　significantly　affect　the　heat　conduction　through　such　kind　of　porous　structures,　reflecting　a　topologically　based　effective　thermal　conductivity.　This　paper　presents　a　novel　geometric　model　for　representing　the　microstructure　of　graphite　foams,　with　simplifications　and　modifications　made　on　the　actual　pore　structure　of　graphite　foam.　For　calculation　simplicity,　we　convert　the　realized　geometry　consisting　of　complex　surfaces　and　tortuous　ligaments　into　a　simplified　geometry　with　circular　ligaments　joined　at　cuboid　nodes,　on　the　basis　of　the　volume　equivalency　rule.　The　multiple-layer　method　is　used　to　divide　the　proposed　geometry　into　solvable　areas　and　the　series-parallel　relations　are　used　to　derive　the　analytical　model　for　effective　thermal　conductivity.　To　physically　explore　the　heat　conduction　mechanisms　at　pore　scale,　direction　numerical　simulations　were　conducted　on　the　reconstructed　geometric　model.　Achieving　good　agreement　with　experimental　data,　the　present　analytical　model　(based　on　the　simplified　geometry)　is　validated.　Further,　the　numerically　simulated　conductivities　follow　the　model　prediction,　favoring　thermally　that　the　two　geometries　are　equal.　The　present　geometry　model　is　more　realized　and　capable　of　reflecting　the　internal　microstructure　of　graphite　foam,　which　will　benefit　the　understandings　for　the　thermo-physical　mechanisms　of　pore-scaled　heat　conduction　and　micro　structures　of　graphite　foam.