The inspection of the external anticorrosive layer of the pipeline only takes the pipeline body as the sampling object, and the corrosion status of individual pipe body can be indirectly found through excavation. The statistical method is used to carry out the "point for surface" inspection and the "generalization" evaluation, so there are certain limitations.

The full circumferential probe of the detection equipment in the pipeline covers the pipeline body and scans the whole process, which can directly and quickly detect and find the body defects in the pipeline and identify the bending strain in the pipeline. By adopting the in-pipeline detection technology, the condition information of the pipeline body can be obtained, and combined with the analysis of material and structural reliability, the safety state of the pipeline can be comprehensively evaluated.