Abstract: The pipe-in-pipe structure, the polyurethane foam plastics covered by high density polyethylene coating, has the characteristics in heat resistance, corrosion resistance, light weight, high strength, long service life and low thermal conductivity factor. Although it is cost-effective in long-distance pipeline, the corrosion control requirements somewhat can not be met due to its manufacture. In the paper, the application of the pipe-in-pipe structure in Changchun-Jilin oil pipeline is introduced, and the experience in elongating service life of this structure is presented.