The invention relates to an FRP(fiberglass reinforced plastic) anchor rod capable of bearing a high pretightening force and a manufacture method thereof. The anchor rod comprises a glass fiber yarn bundle rope-shaped rod body, bulk glass fiber yarns are twisted in a grouped manner to form glass fiber yarn bundles, and then are twisted in a sinistral manner to form the glass fiber yarn bundle rope-shaped rod body, thread grooves in the surface of the glass fiber yarn bundle rope-shaped rod body are wound by bulk glass fiber yarns which fill and level up the thread grooves, and after being bonded by a resin, the bulk glass fiber yarns are molded and cured. The bulk glass fiber yarns are twisted in the grouped manner to form several glass fiber yarn bundles, and then the glass fiber yarn bundle rope-shaped rod body is formed, the thread grooves in the surface of the glass fiber yarn bundle rope-shaped rod body are wound by the bulk glass fiber yarns which fill and level up the thread grooves, and then are impregnated with the resin, after the bulk glass fiber yarns are bonded by the resin, the rod body of the uncured anchor rod which is bonded with the glass fiber yarns is made to traverse a guide hole of a forming die head, and the uncured anchor rod is shaped into a dextral FRP anchor rod by means of an internal screw thread. By means of the sinistral winding manner of the glass fiber yarns, the tensile strength of the glass fiber yarns can be fully utilized, the torsional strength of the rod body is improved, the high pretightening force of the FRP anchor rod can be guaranteed, the problem that a relatively-large pretightening force cannot be applied to the FRP anchor rod can be well solved, and the usage effect of the FRP anchor rod is excellent.