A remanufacturing method of a drill includes providing a drill with a worn-out area. The drill comprises: a shank part; and a flute part arranged on one end of the shank part. A chisel edge is formed on the front end of the flute part, and the radius of any one of the cross section of the chisel edge is defined as a core thickness; a first blade and a second blade with tilt directions toward the shank part are formed on the two sides of the chisel edge. The first circumferential surface of the first blade and the second circumferential surface of the second blade are respectively extended and spiraled toward the shank part along a periphery of the flute part and form two helical cutting edges, a first debris-discharging groove and a second debris-discharging groove. The first blade comprises a first cutting edge. The first cutting edge and the first circumferential surface define the worn-out area. The method also includes a step of aligning a grinding wheel to the worn-out area; and a step of using the aligned grinding wheel to perform a cutting operation along the helical cutting edge or the first debris-discharging groove to grind and repair the worn-out area of the drill.