Graphene-based polymeric composites have become one of the promising thermal interface materials (TIMs) for the high integration electronic devices due to the excellent intrinsic thermal conductivity of graphene. However, the challenges still remain, such as ordered alignment of graphene in elastic polymer and regulation of phonon scattering at graphene/graphene interface. In this study, a vertically oriented graphene framework within a flexible silicone rubber matrix was fabricated by non-solvent induced phase separation (NIPs) coupled with an in in-situ welding technique. The as-prepared film exhibits an outstanding through-plane thermal conductivity of 29.5W/mK at low graphene loading of 7.5wt%, which indicates an exceptionally high thermal conductivity enhancement per 1wt% graphene content (specific TCE) over 1950%/wt%. Furthermore, the composite films demonstrate excellent conformability inherited from the silicone rubber matrix and achieves low contact resistance of 40-70 Kmm2W−1 under various pressure and interfacial conditions. This study contributes to a deeper insight into the development of the high-performance graphene-based polymeric TIMs.