A novel EVA/unmodified nano-magnesium hydroxide (NMH)/silicone rubber ternary nanocomposite was prepared by using a special compound flame retardant of NMH and silicone rubbet (CFR).The flammability of the ternary composite was studied by cone calorimeter test (CCT).Synergistic effect on flame retardancy was found between silicone rubber and NMH.EVA/CFR ternary nanocomposite showed the lowest peak heat release rate (PHRR) and mass loss rate (MLR) among the samples of virgin EVA,EVA composites.The synergistic flame retardancy of silicone rubber and NMH in EVA system is attributed to the enhanced char layers in the condensed phase that prevents the heat and mass transfer in the fire.