The　anisotropy　of　Sn　crystal　structures　greatly　affects　the　electromigration　(EM)　and　thermomechanical　fatigue　(TMF)　of　solder　joints.　The　size　of　solder　joint　shrinkage　in　electronic　systems　further　makes　EM　and　TMF　an　inseparably　coupled　issue.　To　obtain　a　better　understanding　of　failure　under　combined　moderately　high　(2000　A/cm(2))　current　density　and　10-150A　degrees　C/1　h　thermal　cycling,　analysis　of　separate,　sequential,　and　concurrent　EM　and　thermal　cycling　(TC)　was　imposed　on　single　shear　lap　joints,　and　the　microstructure　and　crystal　orientations　were　incrementally　characterized　using　electron　backscatter　diffraction　(EBSD)　mapping.　First,　it　was　determined　that　EM　did　not　significantly　change　the　crystal　orientation,　but　the　formation　of　Cu6Sn5　depended　on　the　crystal　orientation,　and　this　degraded　subsequent　TMF　behavior.　Secondly,　TC　causes　changes　in　crystal　orientation.　Concurrent　EM　and　TC　led　to　significant　changes　in　crystal　orientation　by　discontinuous　recrystallization,　which　is　facilitated　by　Cu6Sn5　particle　formation.　The　newly　formed　Cu6Sn5　often　showed　its　c-axis　close　to　the　direction　of　electron　flow.