Abstract: Changed a suspension line segment in Gela oil pipeline.As didn't order a kind of special angle bend in advance, makes the tie-in welding between new and old pipe ends difficult to realize smooth transition.Because the new pipeline is not drained out of the water completely after hydraulic test to high pressure with clear water for its leakproofness and pressure tightness, the water remained inside the pipeline froze in winter and made the pipeline rupture by expansion, which both reduces the technical property of the new pipeline and makes it leaking in pipeline test with oil.In light of the above shortcomings, suitable measures are taken, which make the ends tie-in realize smooth transition, ensure pipeline's hydraulic test successfully and make the line change from old one to new one smooth.