Abstract: Libyan Western Pipelines, consisted in two DN400 oil pipelines and a DN800 gas pipeline, are parallel-laid with two pigging stations, 16 valve controlling stations and 10 cathodic protection stations in the pipeline system. The commissioning of cathodic protection system shows that the fluctuation amplitude of pipeline potential is more than the allowable scope, possibly the stray current interference. Testing and analysis on the IR drop (in the case of normal operation of pipeline), whole pipeline protection potential, sync-potential and AC interference are made, which successfully solve several problems in anode grounding resistance of pipeline, power supply in power-free area and stray current interference. The cathodic protection technology makes the cathodic protection parameters of pipeline being in ideal state.