To address the difficulty of sensing the ice bonding state during aircraft electrothermal deicing, an in-situ in-body detection method based on the relaxation polarization effect is proposed. First, the mechanism of the influence of the phase state and molecular thermal motion on the ice adhesion effect is revealed, and the principle of detecting the four ice bonding states based on the complex impedance measurement is elucidated. Then, an integrated functional film for detection and de-icing is designed, and the dynamic change process of the interfacial phase state is characterized in ice melting experiments, which identifies the key features of the ice bonding state sensing, and then establishes the recognition method for the weakening of the ice bonding state. In the pre-stressed de-icing experiment, the method can effectively determine the time range of the ice shedding, which is expected to significantly improve the accuracy of the ice bonding state sensing in the electro-thermal de-icing process and provide key technical support for the energy-efficient electro-thermal de-icing of aircrafts.