<p>In the 5G era, the increasing integration and miniaturization of electronic devices pose severe thermal management challenges. However, large-scale fabrication of graphene films with high flexibility, high thermal conductivity, and excellent mechanical properties remains difficult due to structural defects formed during growth. In this study, a graphene oxide/polyaniline (GO/PANI) composite films with different PANI contents are prepared by combining in situ polymerization with vacuum filtration, resulting in flexible, self-supporting films with controllable structures and good film-forming ability. The regulatory effects of PANI on the stacking of graphene sheets, defect density, and interfacial interaction are clarified, confirming that PANI effectively improves structural ordering. Mechanical performance tests demonstrated that the introduction of PANI significantly enhances both the strength and flexibility of the films, with an optimal overall mechanical performance achieved at a doping level of approximately 8%. Meanwhile, the measurement results verified that the GO/PANI films exhibit higher thermal conductivity and more uniform heat diffusion. Chip-level heat dissipation experiments further validated their capability to effectively reduce hotspot temperatures and mitigate junction temperature rise. This work achieves a significant enhancement in the thermal conductivity of graphene composite films without compromising flexibility, thereby providing an efficient and practical material solution for thermal management in high-power-density electronic devices.</p>