Abstract: The long-distance pipeline buried in the ground long-term, shall be subjected with corrosion, perforation, leaking as time goes by, resulting in environmental pollution, and even causing sudden disaster and endangering personal safety. Therefore, there is an urgent need for corrosion inspection. Corrosion inner inspection technology has been rapidly developed because of its intuitive in nature, accuracy and rapidity. The principle of the magnetic flux leakage inspection technology which is the most common and most practical at home and abroad was discussed. The composition and application of gas pipelines in Xinjiang certain Oilfield of the inspection system based on the magnetic flux leakage principle were introduced. The paper is expected to play a clear summary and guiding role for subsequent inspection.