The invention discloses a preparation method for an arc thread anchor bolt assembly for a wind turbine. A round steel rod is selected and rolled into a billet of the corresponding length in a fixed-length or double-length mode according to the need, the ultrasound+magnetic leakage combined damage detection is conducted on the billet, the heat treatment is conducted on the billet, the straighteningtreatment is conducted on the billet, and the surface oxide scale is removed; the vortex or magnetic powder damage detection treatment is conducted on the billet, and arc threads are rolled at the two ends of a workpiece through a thread rolling machine to obtain an anchor bolt; the round steel rod is selected and discharged to the stipulated size to be used as the billet by using a saw machine,forging, molding and punching are conducted on the billet, the end face and the inner hole are lathed by using a lathe, and the chamfering is conducted; and arc thread inner threads are formed by taping of a screw tap, and the heat treatment is conducted on the workpiece by using a vacuum furnace to obtain a nut. According to the preparation method for the arc thread anchor bolt, material removingbasically does not need, straightening and surface oxide skin removing are only needed, the diameter tolerance before anchor bolt thread rolling is controlled at +/-0.3mm, the material utilization rate is high, the production process is fewer, and the production cost is low.