In order to improve the bonding between Ultra High Molecular Weight Polyethylene fiber (UHMWPE) and resin, the fiber surface need to be modified with functional groups. In the paper, the UHMWPE fiber was chlorinated by NaClO and then grafted with 2-hydroxyethyl methacrylate by Atom Transfer Radical Polymerization. After chlorination and grafting, the surface tensions of fibers achieved to 36.5mN/m and 49.5mN/m, respectively. FTIR-ATR and XPS confirmed that the surface of UHMWPE fiber has been functional modified by hydroxyl and ester function of grafted polyhydroxyethylmethacrylate. Further, it can be seen from SEM that the surface of functional modified UHMWPE fiber was not damaged. Compared to unmodified UHMWPE fiber, the mechanical property of functional modified UHMWPE fiber and epoxy resin composite was greatly improved.