The invention discloses a strong magnetic memory detection device for casing damage. The device comprises a sensor bracket, a sealing nipple and a circuit nipple, wherein the sensor bracket is provided with an adjusting screw stem, a central shaft, a plurality of arched spring measurement arms and a sensor; one end of the central shaft is provided with a threaded section; the sealing nipple is provided with a threaded hole, a cable sealing plug and a threaded ring; the threaded hole is matched with the threaded section of the central shaft; a circuit nipple is provided with an internal circuit, a circuit protection cylinder, a lower joint and an upper joint; the lower joint is provided with a threaded section; and the threaded ring of the sealing nipple is matched with the threaded section of the lower joint. In the strong magnetic memory detection device for the casing damage, the magnetic memory characteristic of a ferro-magnetic material is used, a stress concentration part and the magnitude of stress concentration level of a metal material can be accurately detected, and the stress distribution of a bushing can be judged by analyzing the magnitude of the stress concentration level to fulfill the aim of early diagnosis.