The beta-silicon carbide (beta-SiC) micro particles modified by silane coupling reagent of gamma-glycidoxy propyl trimethoxy silane (KH-560) were employed to prepare beta-silicon carbide/epoxy resin (SiC/EP) by blending-casting moulding method to acquire polymer composites with high mechanical properties. Mechanical tests demonstrate that, both the flexural and impact strength of the composites increased firstly with the increasing content of SiC, but decreased with excessive addition of SiC. When the mass fraction of SiC was 10%, the mechanical properties of SiC/EP composites were maximum. Meantime, the use of SiC particles modified by KH-560 significantly enhanced mechanical properties of SiC/EP composites. The surface performance of SiC was characterized and analyzed by XPS, FTIR and TGA. The results indicated that a chemical bonding formed between KH-560 and SiC, and a layer of organic single molecule membrane formed on the surface of SiC. And the maximum mass fraction of KH-560 coated on the surface of SiC was about 2.62%.