Abstract: The application practice of how to carry out internal inspection of long distance pipeline with local elliptic deformation under the specific condition that local pipe change cannot be carried out was discussed. Through the modification of the connecting arm, the cup flange and the probe of the magnetic flux leakage (MFL) testing equipment, the passing ability of the testing equipment at the 3D (inner diameter) bend were improved, and the safety goal of no stuck pigging accident was realized. Through the field measurement analysis and comparison of the internal detection data, it was verified that the quantization accuracy of the internal detection data reached the Rosen standard. The practical experience was accumulated for carrying out internal inspection work under the specific conditions of local elliptic deformation and other deformation of long-distance pipeline in the future, and provided a certain reference for the internal inspection, technical management and safe operation of similar pipelines.