The application of electrothermal anti-icing/de-icing technology in composites represents a key future direction for anti-icing/de-icing research and applications. This study systematically investigated the electrothermal anti-icing/de-icing performance of composites based on carbon nanofilms with superior electrothermal properties. Carbon nanofilms were fabricated via a vacuum filtration method and embedded as electrothermal elements into glass fiber-reinforced polymer （GFRP） composites. An infrared thermal imager was employed to record the temperature distribution ， heating rate， and electrothermal uniformity of the carbon nanofilms and carbon nanocomposites under different applied voltages， so as to evaluate their electrothermal performance in comparison with the commercial PI-Kanthal films. Furthermore， anti-icing and de-icing tests were carried out to evaluate the feasibility of the carbon nanocomposites for practical applications. The results show that carbon nanocomposites exhibit superior heating rates， better electrothermal uniformity， and lower energy consumption compared with PI–Kanthal films. The carbon nanocomposite material has a maximum allowable input voltage of 5 V at room temperature， reaching an equilibrium temperature of 116 ℃ with the input voltage of at 4 V. In anti-icing applications， the equilibrium temperature of carbon nanocomposites reaches 120.1 ℃ at 6 V under -15 ℃. In de-icing applications， ice （0.8 g） detaches within only 130 s at 6 V under -15 ℃， demonstrating the great potential of carbon nanocomposites for anti-icing/de-icing applications.