Abstract: To accurately simulate the aircraft electrothermal de-icing process, the coupling and synergistic effects among multiple physical fields must be considered. In this study, a multi-step icing numerical model and a multiphysics-coupled de-icing model were established, in which the dynamic interactions among the flow field, temperature field, stress field, and ice melting phase change were fully considered. The stress distribution characteristics at the ice-skin interface and within the two-dimensional accreted ice under chordwise local heating conditions during the de-icing process were analyzed, and the critical local heating range was determined based on multiphysics-coupled simulations. Furthermore, the mechanical responses of the ice under different flight velocities, altitudes, and liquid water contents were investigated. The results show that thermo-mechanical coupling induces significant stress responses in the ice, and the melting phase change further promotes stress evolution. A critical local heating range (with a heating coverage of 90%–95%) is identified. Under this condition, the shear stress exceeds the shear strength over more than 90% of the ice-skin interface, while the minimum principal stress exceeds the compressive strength over more than 99% of the ice near the ice-skin interface. These findings provide numerical support for analyzing the mechanical behavior of ice during aircraft electrothermal de-icing processes.