The invention relates to an organic 
silicon encapsulating material for a high-power LED and a preparation method thereof. The organic 
silicon encapsulating material is prepared by mixing a component A containing vinyl polysiloxanes, a 
silicone resin component B, a component C containing 
hydrogen polysiloxane, a 
platinum catalyst component D, a component E of catalytic inhibitor of 
acetylene alcohols and a 
tackifier component F. The obtained encapsulating 
silicon rubber with different refractive indexes of level 1.4, level 1.5 and the like can be used for the encapsulation of various high-power LEDs and the encapsulation of other optical application. The organic 
silicon rubber encapsulating material for the high-power LED takes the 
silicone resin component B as a filling material, which not only enables that the 
silicone rubber has high transparency, high strength and high light 
transmittance, but also improves the 
temperature resistance, the yellowing resistance, and the durability of the high light 
transmittance of high-power LED products. The organic 
silicon rubber encapsulating material for the high-power LED can be prepared into two encapsulating forms of a 
single component and bi-component, which improves the adaptability and the encapsulating efficiency for encapsulating equipment and process procedures, and has the characteristics of reduced cost and convenient use.