Silicone rubber/mineral powder composites have been prepared by surface modification and ultratinecrashing of mineral powder, mixing and vulcanizing with silicone rubber resin. The surface and interface energy for mineral filler and silicone rubber matrix were investigated. It was found that there is a correlation between W-a/sigma(SL) (interfacial adhesive work/interfacial tension) and the tensile strength of the corresponding composite, especially for unmodified ultrafine mineral filler. On the other hand, the chemical modification of the surface changes the surface group on the mineral filler and results in improvement of the interfacial interaction between silicone rubber matrix and mineral filler, consequently, altering the reinforcing effect of the mineral filler.