Nano-silver　paste　is　widely　used　in　silicon　carbide　(SiC)　power　devices,　where　SiC　power　devices　possess　the　characteristics　of　high　junction　temperature　and　high-power　density,　which　could　lead　to　generation　of　heat　dissipation　issues　during　work.　As　the　most　critical　part　of　the　heat　transfer　of　the　entire　device,　the　solder　layer　may　have　a　significant　effect　on　the　heat　dissipation　performance　and　lifetime　of　the　entire　device　during　the　service,　due　to　its　porous　structure　when　the　sintering　process　is　completed.　Therefore,　must　be　pay　attention　to　the　thermal　behavior　of　sintered　nano-silver.　In　this　paper,　a　two-dimensional　random　generation　method　for　the　establishment　of　sintered　silver　layer　is　proposed.　The　heat　transfer　performance　of　sintered　silver　is　expressed　by　the　equivalent　thermal　conductivity,　which　is　calculated　by　a　numerical　method,　and　the　effect　of　sintered　silver　microstructure　on　thermal　conductivity　is　also　analyzed.　The　simulation　results　show　that　the　equivalent　thermal　conductivity　reduces　gradually　when　the　porosity　of　microstructure　increases.　The　heat　transfer　performance　of　sintered　silver　layer　can　be　estimate　by　this　method　under　various　conditions.