The　critical　current　density　and　temperature　endured　by　solder　joints　are　identified　as　the　two　most　important　parameters　that　determine　the　occurrence　of　electromigration　(EM).　It　is　well　known　that　movement　of　metal　atoms/ions　during　current　stressing　can　induce　obvious　stress　concentrations　at　the　anode　and　cathode　interfaces　of　the　solder　joint.　Therefore,　the　global　average　effects　of　EM　on　stress　evolution　at　both　the　anode　and　cathode　interfaces　were　investigated　with　different　current　densities　by　employing　a　nondestructive　x-ray　diffraction　technique.　The　ultimate　results　indicated　that　the　compressive　stress　increased　gradually　at　the　anode　side　under　low　current　density.　However,　stress　fluctuation　could　be　observed　under　high　current　density　due　to　an　obvious　Joule　heating　effect.　For　further　understanding　of　the　mechanism　of　stress　evolution　in　the　solder　joint　during　current　stressing,　a　four-stage　model　is　considered.　First,　Cu　expansion　led　to　increase　of　the　compressive　stress　at　both　electrodes.　Second,　stress　relaxation　compensated　the　compressive　stress　and　caused　it　to　decrease.　Third,　the　EM　effect　promoted　compressive　stress　and　tensile　stress　at　the　anode　and　cathode,　respectively.　Finally,　a　steady　state　of　stress　was　achieved　at　the　anode,　while　the　state　of　tensile　stress　at　the　cathode　remained　transient.