Abstract: The recycliing pipe of an abandoned subsea oil-water mixed pipeline was evaluated by macroscopic inspection, mechanical property testing, corrosion product composition analysis, etc. And the corrosivity of the medium in this pipeline was analyzed by water quality analysis, scaling trend prediction, bacterial test and indoor corrosion simulation test. The results showed that the inner wall of the pipeline was seriously corroded, the corrosivity of the medium was high. The inner wall of the pipeline suffered CO₂ corrosion, as well as under-scale corrosion and bacterial corrosion. Based on the results of corrosion detection and evaluation of the recycliing pipe section, the opinions and measures for the corrosion control and integrity management of the new subsea oil-water mixed pipeline in the oilfield were proposed.