<p>In the intersection of electrical and biomedical engineering, high-performance insulation materials are crucial for ensuring the safe and reliable operation of medical devices. Due to its excellent dielectric properties, chemical stability, and biocompatibility, fluorinated ethylene propylene has demonstrated significant potential in high-frequency and high-voltage medical applications. However, under intense electric fields, the microstructure of fluorinated ethylene propylene can undergo evolution, leading to degradation of its insulation performance and posing risks to device safety. Conventional experimental methods struggle to capture the real-time nanoscale response of materials to electric fields. To address this limitation, a first-principles study based on density functional theory was conducted to systematically investigate the microscopic mechanisms by which external electric fields influence the molecular structure, electronic properties, polarization behavior, and vibrational spectra of fluorinated ethylene propylene. The results indicate that the applied electric field induces conformational changes, enhances bond polarization, narrows the energy gap, and alters the frontier molecular orbitals of the polymer, thereby affecting charge carrier dynamics and trap state distribution. Additionally, shifts in characteristic infrared absorption peaks reveal the electric field’s modulation of bond vibrational modes. Collectively, these microscopic insights elucidate the fundamental physical mechanisms underlying the insulation performance degradation of fluorinated ethylene propylene under strong electric fields, providing a theoretical foundation for assessing insulation reliability and guiding material optimization in medical electronic devices.</p> Graphical Abstract <p></p>