Abstract: This paper introduces the principle of defect detection of metal pipelines by using electromagnetic method, builds a test bench to verify the feasibility of defect detection of metal pipelines by using electromagnetic method and carries out experimental analysis on the influencing factors of metal pipeline detection by using electromagnetic method, mainly including excitation current, frequency, lift-off height, defect location and defect type. The test results can provide technical support for later sensor optimization and inspection in actual working conditions, which can provide reference for defect detection of metal pipes with coating.