Abstract: The gear system plays a very important role in the mechanical equipment and its performance often has a decisive influence on the whole equipment.The simulation and experimental studies focus on the gear magnetic memory effect under high-cycle fatigue.Firstly,the three-dimensional models of normal and crack gear are established,and the constraint and loading are applied in static analysis to get the gear stress.Secondly,the relative permeability in the gear stress concentration areas are divided according to the relationships between stress and relative permeability with the magnetization.Thirdly,geomagnetic field models are created,and the specimens are used in the model to simulate the magnetic induction.Finally,the gear fatigue test was carried out on a high-cycle fatigue machine,and the magnetic memory signals around the whole tooth root were picked up for comparative analysis.The results verify the correctness of the simulation process,and provide a theoretical basis for the use of magnetic memory testing technology for diagnosis of early gear failure.