In this study, glass fiber (GF) was grafted by an amino-terminated hyperbranched polymer (ATHBP). The structure of GF-ATHBP was characterized by attenuated total internal reflectance infrared spectroscopy, H-1 nuclear magnetic resonance spectroscopy, thermal gravimetric analysis, and field emission scanning electron microscopy (FESEM). The modified GFs were used to produce high-performance epoxy composites. The effects of GF-ATHBPs on the mechanical properties of composites were investigated, discussing the results from tensile, flexural, and impact tests. The results showed that the grafting ratio of ATHBP on GF was 7.6 %, and the thickness of ATHBP layer was about 1.9 mu m. And the incorporation of GF-ATHBPs could favorably improve the mechanical properties of epoxy resins. FESEM morphologies showed that the excellent compatibility and interaction may be associated with the great enhancement of mechanical properties of epoxy/GF-ATHBP composites.