Abstract: Purpose About the issues of high dependence on physical models and the lack of numerical simulation methods for the magnetic evolution of ship deperming technology, a numerical simulation method based on the equivalent magnetic domain model is proposed for the magnetic evolution of ship deperming.Method Firstly, based on the analysis of the theoretical morphology of magnetic domains, an equivalent magnetic domain mathematical model is established using the magnetic dipole model; Then, analyze the fundamental motion theory of magnetic domains from the perspective of static magnetic energy and establish a mathematical motion model; Finally, based on the MATLAB numerical simulation platform, numerical simulations and ship model experiments were conducted to verify the evolution law of ship deperming magnetism. ResultThe results showed that the numerical model of ship magnetic domains achieved magnetic equivalence of the ship model, with a relative error controlled at 17.04%; The numerical simulation of the demagnetization evolution process conforms to the magnetic change law of the ship model deperming physics process. After AC deperming, the residual fixed magnetic field peak accounts for 15% of the original fixed magnetic field peak, and the relative error of the fixed magnetic field peak after no hysteresis magnetization is 2.58%, which verifies the effectiveness of the numerical simulation method. Conclusion This numerical simulation method can achieve a mirror image of the magnetic evolution law from physical space to digital space in ship deperming work, and can intuitively and dynamically present the magnetic evolution law during the deperming process, laying a certain theoretical foundation for the digital image of the entire process of ship deperming.