Abstract: The structural deterioration and damage of the oil and gas pipelines are quite uncertain in terms of temporal and spatial distribution. To assess the structural state of buried pipelines in real time, a buried pipeline monitoring scheme based on the distributed optical fiber sensor was proposed and a distributed monitoring data based method was developed to assess quantitatively the structural state of buried pipelines. It is demonstrated from the application cases that the monitoring scheme based on the distributed optical fiber sensor can be connected seamlessly with the construction process of buried pipelines, so it is convenient for practical operation. By virtue of the distributed optical fiber sensor, the temporal and spatial evolution of the bending strain and temperature of the buried pipelines can be monitored accurately, so the restriction that commonly used point sensor cannot cover the whole pipeline is eliminated. The structural state of buried pipeline can be assessed quantitatively in real time by using the distributed monitoring data of bending strain and temperature of the pipeline, combined with the monitored material, geometric parameters and internal pressure of pipeline. This method provides the basis for the assessment on the lifecycle structural state of buried pipelines.