One of the dangers of storing materials in storage tanks is the leakage of materials due to corrosion to the surrounding environment, which in addition to cause damage due to the loss of valuable material and environmental pollution, can lead to accidents. PCM method is one which is used for inspecting Pipelines by electromagnetic method. Electromagnetic fields easily pass-through soil, water, asphalt, etc. Therefore, without drilling and through the ground, Pipelines are inspected and monitored. By measuring the amount of induced alternating current in its strong magnetic sensors, it is able to detect the current amount in Pipelines, the position of sacrificial anodes, the quality of coating, and the location of its defects. In this method, alternating current is used to inspect Pipelines. By increasing the frequency of alternating current, the inductive effect of this method increases on foreign structures and adjacent metal structures. In this case, by using different frequencies as well as very low frequencies, they eliminate the impact of adjacent foreign structures on the Inspection results.