Abstract: The effects of chemical structure,composition of epoxy resin,curing time,accelerants,as well as particle diameter,activity,insulation grade and dosage of silicon dioxide filler with respect to its mechanical properties were investigated by determining impact strength and flexural strength of modified-rosin-based epoxy resin.It was shown that chemical structure and composition of epoxy resin were the main factors affecting the mechanical properties of epoxy resin materials.The mechanical properties of epoxy resin material were the best at 120℃ curing about 6-8 h with the accelerant DCT-1 when weight ratio of silicon dioxide filler to epoxy resin was 2.5 to 1.