Electron　beam　welding　(EBW)　with　multi-beam　is　a　novel　method　to　decrease　weld　cracks,　which　is　suitable　for　welding　the　parts　in　aero　industries.　We　studied　EBW　with　multi-beam　on　high　temperature　titanium　alloy,　which　was　refers　to　simultaneous　EBW　with　electron　beam　(EB)　preheating　or　post-heating.　We　proposed　the　ratio　of　the　power　for　welding　and　preheating　or　post-heating,　and　modeled　temperature　fields　and　temperature　histories　by　ABAQUS　software.　The　results　showed　the　temperature　of　EB　post-heating　was　higher　than　that　of　EB　preheating,　and　EB　preheating　and　post-heating　respectively　lowered　the　temperature　gradient　of　welding　heating　and　welding　cooling,　which　improved　the　uniformity　of　the　temperature　of　EBW.　The　weld　morphologies　were　consistent　with　those　of　the　modeling,　which　verified　the　feasibility　and　effectiveness　of　the　temperature　fields　modeled.　The　microstructures　of　the　welds　with　post-heating　were　coarser　than　those　with　preheating.　The　microhardnesses　of　the　welds　with　preheating　and　post-heating　were　more　homogeneous.　The　influences　of　EB　preheating　and　EB　post-heating　on　EBW　were　discussed.　(C)　2013　Elsevier　Ltd.　All　rights　reserved.