solder　joint　thickness　has　an　important　effect　on　the　fatigue　failure　behavior　of　solder　joint.　In　this　study,　fatigue　behavior　of　solder　joints　with　different　solder　thickness　(0.1mm,　0.2mm,　0.3mm)　were　studied　under　398K.　The　failure　path　and　rupture　morphology　were　observed　utilizing　scanning　electron　microscopy　(SEM)　in　order　to　reveal　the　failure　mechanism.　Moreover,　fatigue　life　was　evaluated　using　the　Coffin-Masson　model　and　the　influence　of　solder　thickness　on　the　fatigue　exponent　and　coefficient　was　analyzed.　The　result　shows　that　fatigue　life　of　solder　joint　increases　with　the　solder　thickness.　Solder　joins　of　lowest　thickness　has　the　fast　maximum　load　drop　rate.　Besides,　the　fatigue　ductility　exponent　in　Coffin-Masson　model　decrease　with　the　solder　thickness,　so,　the　higher　solder　thickness　means　super　fatigue　resistance.　On　the　other　hand,　fatigue　crack　is　initiated　at　the　corner　of　the　solder　joint,　and　propagated　in　the　solder　matrix　with　a　direction　paralleling　to　the　loading　direction.　A　deformation　concentrated　zone　along　the　diagonal　of　solder　joint　is　formed　with　increasing　the　solder　thickness,　inducing　a　step-like　fracture　morphology　and　all　samples　show　a　ductility　rupture　mode.