Abstract: Induction brazing is a key process in the manufacturing of squirrel-cage rotor; however, the complex multi-physical field interactions involved still lack a clear quantitative understanding. To address this gap, this work establishes a multi-physics mathematical framework coupling electromagnetic and thermal fields to systematically investigate the dynamic evolution of the temperature field during the induction brazing process. Furthermore, an equivalent heat source model incorporating the skin effect is developed to enhance computational efficiency while maintaining accuracy. Numerical results demonstrate that the equivalent heat source model exhibits excellent agreement with the full coupled model in predicting temperature field uniformity, with a peak temperature deviation of merely 3.5%. The accuracy of the simulation results was validated through real-time infrared temperature monitoring.