The invention discloses a repairing method for the local defect of concrete in a water level change region and a repairing device. The repairing device comprises a template, a stainless steel plug bolt and a plurality of inclined support rods, wherein the template is used for covering a defected cavity of concrete, water stopping rubber strips are arranged around the inner surface of the template, air holes capable of being opened and closed are arranged in the top of the template, and grouting holes capable of being opened and closed are arranged at the bottom of the template; the stainless steel plug bolt is fixedly connected with the center part in the defected cavity of the concrete, and the template is fixedly connected with the outer side of the defected cavity due to the match among bolts, positioning nuts and sealing nuts, so that the defected cavity of the concrete can be completely covered by the template; a counter-pull screw rod is in butt joint with a free end of the plugbolt by a sleeve, and an inclined rod support disc is rotatablely connected to the counter-pull screw rod; and the inclined support rods can adjust the lengths of rod bodies, one end of each inclinedsupport rod is supported on the outer surface of the template, and the other end of each inclined support rod is supported on the inclined rod support disc. The device disclosed by the invention has the characteristics of being simple in structure, sealed and waterproof, light and portable, easy to operate on the spot and the like.