Graphene films have attracted much attention as a heat dissipation material due to their unique thermal transfer behavior that exceeds that the performance of graphite. However, the very high thermal annealing temperature (similar to 3000 degrees C) required to reduce the graphene oxide (GO) films leads to high manufacturing costs and restricts its broader application in thermal management applications. In this study, a modified-graphene (m-Gr) film was fabricated by vacuum-filtering GO suspensions with added glucose, followed by thermal annealing at 1000 degrees C. Oxygen-containing functional groups were effectively eliminated during annealing and activated carbon atoms from the decomposition of glucose molecules repaired defects in the graphene sheets to restore large areas of the pi-conjugated structure. The as-obtained m-Gr films showed excellent in-plane thermal conductivity similar to 1300 Wm(-1) K-1 and much more efficient heat removal than pristine-reduced graphene oxide films. This high thermal conductivity of m-Gr films provides opportunities for their use in next-generation commercial electronics.