Abstract: In the light of coating ageing, resistance increment of anode groundbed, reference electrode failure and breakdown of 4-core cable in three oil pipelines of Daqing Oilfield, the detection on resistance of anode groundbed, current leakage at the location of cathodic disbanding and insulating resistance of coating is conducted. The countermeasures in cathodic protection, CP system management, monitoring method and pipeline maintenance are proposed. The evaluation on protection results of the measures taken is carried out.