Abstract: The paper has analyzed the phenomenon of corrosion and oil leakage, which had been taken into place for some times and some positions in Cengzhou-Linyi 0il Pipeline even under the condition of cathodic protection, 1t has pointed out the close relationship between pipeline corrosion pinhole and soil medium, rainfal and underground water level.lt is the first time for putting forward the new concept of "dead spot for protection" existed in buried pipeline as well as the way of overcoming "dead spot for protection" .