Electrothermal deicing is recognized as a reliable method for aircraft ice protection. To systematically investigate the internal temperature variation and the ice-shedding process of the airfoil during multi-cycle deicing operations， this study establishes a coupled numerical simulation framework that integrates water film flow and transient heat transfer. The proposed model incorporates distinct conjugate heat transfer configurations for “water film/ice layer/wing” and “water film/wing” systems， explicitly accounting for the dynamic effects of ice accretionand shedding. The validity of the proposed model is verified through comparison with experimental data.Comparative analysis of the computational results from multi-cycle electrothermal deicing reveals that the continuously energized heated zone， functioning as a thermal knife， leads to an expansion in the coverage of both overflow water and ice accretion， accompanied by increased ice accretion in downstream heated zones. The results demonstrate that the proposed numerical model achieves a maximum deviation of less than 3 K in temperature profiles compared to experimental data throughout multiple electrothermal deicing cycles. Furthermore， it accurately predicts the evolution of both the runback water and ice accretion.