Abstract: This article aims to introduce the metal magnetic memory testing technique which is important on fatigue damages and early diagnosis of ferromagnetic components.Some unique advantages about metal magnetic memory testing technique, mechanism and instruments of metal magnetic memory testing were described by analysis and comparison.The study on the mechanism and the application of the method at home and abroad was introduced and two cases of analysis were provided. At last, some current problems and the possible direction of future development about metal magnetic memory testing technique were summarized.