Heat dissipation problems have limited the further development of the chip technique, therefore, searching for thermal interfacial materials with high thermal conductivity becomes one of the most important methods to break through the bottlenecks. Among these thermal interfacial materials, organic-inorganic composites are believed to be a promising alternative of the traditional silicon grease, due to their flexibility and controllable thermal conductivity. The fabrication methods of organic-inorganic composites, such as physical blending, phase precipitation, in-situ oxidation have been widely adopted on experiment. In this paper, we fabricated the polyvinylidene fluoride/graphene composites by using physical blending method, and their thermal conductivities could achieve as high as 83 W/(m·K) by using non-steady measurements with temperature T＝360 K and volume ratio f＝76 vol%. Furthermore, the thermal conductivity of the organicinorganic shapes, and the interactions between the organic and inorganic materials. We adopted the improved Bruggeman model and Agarimodel based on the effective medium theory to explain the thermal transport mechanism. Investigation results showed that, improved Bruggeman model cannot interpret the reason of high thermal conductivity of composites. The larger the fraction of the fillers, according to Agari model, the easier could the thermal conductive channels form among the fillers, thus the higher the thermal conductivities of these composites. composites is highly depends on factors including the volume ratio of the fillers, grain sizes and