In　this　study,　porosity　effect　on　fatigue　life　of　sintered　silver　layer　in　SiC　power　devices　was　predicted　by　nonlinear　finite　element　analysis　(FEA).　A　microstructure　model　of　sintered　silver　with　sphere　and　Primitive　(P)　structure　as　the　pore　shape　was　established　in　which　a　viscoplastic　constitutive　relation　is　adopt　for　sintered　silver.　The　evolution　of　the　maximum　equivalent　stress　and　maximum　equivalent　viscoplastic　strain　in　the　sintered　silver　layer　under　thermal　cyclic　loading　(-40　°C　to　150　°C)　was　simulated　by　ABAQUS　based　on　the　sub-model　technique.　Near　the　corners　of　the　sintered　silver/copper　substrate　interface,　the　equivalent　stress　and　viscoplastic　strain　of　the　sintered　silver　layer　are　concentrated.　The　empirical　life　model　based　on　the　Coffin-Manson　rule　was　used　to　predict　the　fatigue　life　of　the　sintered　silver　layer,　and　the　impact　of　various　porosities　was　examined.　It　was　found　that　the　increase　of　porosity　for　sphere　and　Primitive　(P)　structure　pores　leads　to　a　decrease　of　sintered　silver　fatigue　life.　　©　2022　IEEE.