Abstract: The surfaces of the glass fibers were modified by the silane coupling agent KH-550, and the glass fibre/epoxy resin composites were prepared. The composites were decentralized by ultrasonic dispersion, effects of different ratios of milled glass fiber powders on the compression and tensile properties of epoxy resin composites were discussed. The results showed that the strength and hardness of the epoxy resin increased after the addition of the milled glass fiber. When the addition of glass fiber was between 15%~25% (w), the mechanical properties of the composites improved, and the compression strength, compression modulus and tensile strength were up to 67. 1 MPa, 1. 68 GPa and 57. 6 MPa, increasing by 24%, 35% and 34% compared with those of pure epoxy resin, but the elongation at break decreased gradually with the increasing of addition and decreased by 48% compared with that of pure epoxy resin when the content reached 30%, showing that the brittleness of epoxy resin deterioted after adding glass fiber. The glass fiber with larger mesh size had better effect on the mechanical properties of epoxy resin, but the influence was not as great as that of the content of filler.