The　growth　kinetic　of　intermetallic　compounds　(IMCs)　and　fatigue　failure　behavior　of　SnAgCu/Cu　solder　joints　subjected　to　thermal　cycling　have　been　investigated.　An　equivalent　IMC　growth　equation　for　thermal　cycling　and　a　heterogeneous　model　for　solder　joint　interface　were　proposed,　and　the　finite　element　(FEM)　simulation　was　applied　to　analyze　the　stress/strain　field　distribution　on　solder　joint　interface　as　well　as　the　failure　mode　of　solder　joints　subjected　to　thermal　cycling.　The　results　show　that　the　lower　the　cryogenic　temperature　limit　of　the　thermal　cycling,　the　lower　the　fatigue　life　of　the　solder　joint.　Failure　mode　of　solder　joints　exhibits　solder　fatigue　failure　with　failure　site　close　to　solder/IMC　interface.　The　thicker　the　IMC　layer,　the　more　accumulated　plastic　work　density　in　solder　joint,　as　a　result,　the　solder　joint　with　a　thicker　IMC　layer　is　more　prone　to　failure.