Food safety analysis and clinical diagnosis are closely related to people"s health. How to improve the ability of food safety analysis and clinical diagnosis have always been the focus of all over the world. As an efficient and convenient method, rapid detection has been considered as an important means to break through this problem. And magnetic relaxation switching (MRS) biosensor has become a new tool for rapid detection due to its excellent analytical performance and simple analysis process, which has been used in the field of public health. In order to improve the performance of the MRS biosensors, researchers have done a lot of works such as exploring effective signal conversion mechanism, constructing new nanometer magnetic probe, developing efficient signal amplification system and improving the stability of the sensor, which has greatly promoted the development of rapid detection. In this paper, different sensing mechanisms, recent research progress and applications of MRS biosensors are reviewed.