Microstructure　of　pure　copper　straight　tubes　with　and　without　bending　defective　were　investigated　and　characterized　by　optical　microscope　(OM)　and　electron　backscatter　diffraction　(EBSD)　techniques,　respectively.　The　results　show　that　the　tube　microstructure　is　fibrous　and　parallel　to　the　axial　direction　of　the　tube,　which　produces　strong　＜111＞　and　＜100＞　texture　in　the　material,　while　the　twin　boundaries　mainly　appear　in　the　＜111＞　texture.　So　it　is　considered　that　the　possible　cause　of　straight　tube　wrinkles　and　cracks　may　be　that　a　large　number　of　＜111＞　texture　will　form　more　twins.　©　2018,　Editorial　Office　of　＂Jinshu　Rechuli＂.　All　right　reserved.