The linear epoxy-aminopropyltriethoxysilane addition polymer is used as a new epoxy modifier in is paper. The glass transition tempeuture (Tg) add thermal degradation character have been determined using differential scanning calorimetry(DSC). The experimental results show that copolymer modifier can effectively decrease Tg of resin without sacrificing thermal resistance. The properties of epoxy resin blended with aminopropyltriethoxysi1ane (γ-APS) are also carried out simultaneously as a comparison.