To　explore　the　buckling　form　of　the　straight　long　tube　under　complicated　conditions,　the　buckling　analysis　based　on　the　beam-to-beam　contact　theory　is　carried　out.　The　beam　is　discretized　according　to　the　beam-to-beam　contact　theory　in　consideration　of　shear　and　bending　deformation.　The　finite　element　method(FEM)　model　considering　the　variable　section　and　frictional　contact　is　built,　where　the　tube-to-tube　contact　element　is　used.　By　using　this　method,　the　FEM　model　concerned　with　the　layered　production＇s　actual　working　conditions　is　presented.　The　result　turns　out　that　the　tube＇s　buckling　form　under　the　complex　condition,　is　multiple　and　not　equidistant.　Moreover,　the　buckling　form　with　friction　is　not　the　standard　sine　type　or　the　spiral　configuration,　and　the　reliability　of　these　results　has　been　proved　by　the　magnetic　positioning　data.　©　2017,　Periodical　Office　of　China　University　of　Petroleum.　All　right　reserved.