Abstract: By surface covering modification technology, nano CeO₂ was modified by stearic acid, the modified nano m-CeO₂ and phenyl hydrogen containing silicone resin (PH) were chemically graftinged to prepare m-CeO₂-PH grafting. Atransparent m-CeO₂/phenyl-silicone rubber materials used for light-emitting diode (LED) packaging materials were prepared by the method of hydrogenation with grafting as cross-linking agent under the platinum catalyst.The results show that stearic acid salt produces on surface of m-CeO₂ after modified by stearic acid, which increases the compatibility of the interface and improves the dispersion of nano CeO₂ in polymer. m-CeO₂ was grafted in PH system by chemical method, then reacted with phenyl vinyl silicone resin (PV) with stoichiometric ratio under catalyst, and functional m-CeO₂/phenyl-silicone rubber materials were prepared through high temperature curing. Research shows that the light transmission rate of m-CeO₂/phenyl-silicone rubber materials reaches above 85% with 0.02% mass fraction of m-CeO₂, and ultraviolet aging properties and mechanical properties increase obviously. In addition when 0.02% mass fraction m-CeO₂ was introduced in phenyl-silicone rubber materials and decomposition temperature of CeO₂/silicone rubber composites is 600℃, the thermel gravimetric loss rate of m-CeO₂/phenyl-silicone rubber materials will cut down 8% than pure phenyl-silicone rubber, heat release of m-CeO₂/phenyl-silicone rubber materials is obviously lower than that of pure phenyl-silicone rubber which has superiority for LED packaging materials.