Abstract: Non-destructive testing techniques have very important influence on guaranteeing safety production of drilling and repairing rig platforms, and ACFM method is now in widespread use because of its many advantages such as non-contact measurement, qualitative and quantitative measurement once without calibration. The detection principle, testing system, examination standards and certification of ACFM technique are simply introduced and compared with other non-destructive testing methods including ACPD and ET. Taking the critical welded seams of drilling derrick and substructure and the platform crane for examples based on the drilling and repairing rig platforms, the instrument selection, probe scanning and result diagnosis of the ACFM method applied to engineering practice are illustrated in detail, and interference factors and corresponding processing methods during testing are analyzed. At last, potential fields and solving ideas of the ACFM method applied to detect drilling and repairing rig platforms are discussed.