In　this　work,　the　boundary　structure　of　the　(332)＜　113　＞(beta)　deformation　twin　in　a　deformed　metastable　beta-type　Ti-Nb-Pd　alloy　has　been　clearly　revealed　by　means　of　high-angle　annular　dark-field　scanning　transmission　electron　microscopy　at　atomic-resolution　level.　It　is　found　that　stress-induced　alpha＂　martensite　structure　remains　in　the　{332}(beta)　twin　boundary　region,　exhibiting　a　gradual　transition　to　the　13　structure　with　an　orientation　relationship　of　(1(3)over-bar0)(alpha＂)//(332)(beta).　This　finding　provides　a　direct　experimental　evidence　to　verify　that　the　formation　of　a　(334　twin　in　deformed　metastable　(beta-type　Ti-Nb-based　alloys　can　be　associated　with　a　reversible　beta-to-alpha＂　martensitic　transformation.　(C)　2018　Acta　Materialia　Inc.　Published　by　Elsevier　Ltd.　All　rights　reserved.