Abstract: Accidents of drilling thread and pipe fracture are easy to occur near the wellhead, the neutral point and the bottom hole,the exploration and development process of oil and gas resources was therefore seriously affected. To solve this problem, this article applied metal magnetic memory detection technology to monitor the drill string damage state during the drilling process, and the technology was put into practice in ZG301H well of Tarim Oilfield to conduct damage detection test. The analysis method of the magnetic memory signal in the thread joint of drill string is studied, the relationship between the magnetic memory signal of the thread and tube body with the well depth is established, and the typical drill string with larger stress concentration is analyzed. It can avoid injured drilling tools being brought into the well, and it is of great significance for preventing the occurrence of fatigue fracture.