Abstract: Abstract Aiming at the problem of weld defects in oil and gas pipelines, several electromagnetic detection technologies of pipeline weld defects were analyzed deeply, defect types and failure reasons were pointed out. The basic principle, structure, characteristics and some limitations of various electromagnetic nondestructive testing methods were summarized. The research progress of eddy current, electromagnetic ultrasound, magnetic leakage and magnetic disturbance at home and abroad was introduced. Finally, the development prospect of pipeline weld defect detection technology was summarized.