Nowadays,　the　combination　effects　of　thermal,　mechanical　and　electrical　on　the　reliability　issues　of　solder　joint　gain　more　and　more　attentions.　The　independent　failure　mechanisms　of　solder　joints　are　widely　investigated　and　comprehended　under　single　conditions　as　listed　above.　However,　the　coupling　effect　of　thermal,　mechanical　and　electrical　needs　further　exploration.　Consequently,　the　failure　behaviors　of　solder　joint　under　coupling　of　high　current　density　and　creep　become　a　critical　problem.　The　sandwich　Cu/Sn3.0Ag0.5Cu/Cu　solder　joints　which　subject　to　constant　ambient　temperature　and　creep　stress　but　different　current　density　are　systematically　investigated　in　the　study.　The　failure　behaviors　of　solder　is　analyzed　and　discussed　by　observation　of　the　resistance　change,　microstructure　evolution　and　orientation　transition　of　solder　joints.　The　effects　of　mechanical,　thermal,　and　electrical　on　the　damage　calculation　are　also　illustrated　individually.　The　results　indicate　that,　failure　mechanism　of　solder　joint　under　a　constant　creep　stress　of　5.5MPa　and　low　current　density　was　controlled　by　grain　boundary　sliding.　The　damage　easily　accumulated　near　both　interfaces　of　solder/Cu.　The　electromigration　process　could　alleviate　creep　damage　by　released　grain　boundary　sliding　and　changed　stress　distribution　in　the　solder　joint　at　initial　stage.