In order to develop safe electrical insulating epoxy nanocomposites with fast heat dissipation and low fire hazard, a "3D fabrication method" was proposed to employ acid-sensitive metal organic framework (MOF) as precursor to construct sandwich-type three-dimensional (3D) graphene/layered double hydroxide (LDH) hybrid structure (rGO@LDH) with NiCo-LDH platelets standing vertically or lying horizontally on both sides of graphene nanosheets which act as a high-performance nanofiller in epoxy nanocomposite. The LDH sheath encased the surface of graphene, impeding electrical conduction and effectively generating a 3D phonon transport channel prone to fast heat dissipation. A 2 wt% rGO@LDH-treated epoxy nanocomposite sustained an electrical resistivity of 1.21 x 10(14) Omega cm and its thermal conductivity was 0.421 W m(-1) K-1, 81.4% higher than that of pure epoxy resin. Likewise, thanks to the physical barrier and catalytic effects of rGO@LDH, the nanocomposite had low fire hazard indicated by cone calorimeter data showing that peak of heat release rate and total smoke production decreased strikingly compared with those of the pristine one. Moreover, the thermal stability and tensile strength of the nanocomposite were also enhanced in the presence of rGO@LDH. This work advances progress on the development of highly safe multifunctional epoxy nanocomposite for practical use.