Objective To identify the cause of outer coating damage factors and the effect of damaged anticorrosive coating on thickness reduction of the pipe wall. Methods PCM + buried pipeline external coating condition detector was used to detect the pipeline external coating, collect burial depth, DB value and current attenuation value and calculate insulation resistance rates based on the current value. Remaining wall thickness of the pipeline was detected by ultrasonic thickness meter. Pipeline coatings and wall corrosion conditions were analyzed based on the field data. Results According to data analysis, operating years, burial depth, medium transmission temperature and soil resistance rates, etc. all had different degrees of impact on external anticorrosive coating. Different materials of external anticorrosive coating had different degrees of damage and different impact on thickness reduction of pipe wall with the growth of its operating years. Conclusion Pipeline that has run for more than one decade should be regularly checked and maintained and its anticorrosive coating should also be regularly replaced. For the pipeline with depth less than 0.8 m, the overburden thickness should be increased in time. If the depth can not be increased, inspection should be intensified to avoid pipeline damage. As asphalt glass cloth that has run for more than one decade is damage extensively, the anticorrosive coating should be replaced with 3PE coating. Cathodic protection system should be established to form a double barrier with the external anticorrosive coating.