Casing coupling reverse buckling device and using method thereof

The invention discloses a casing coupling reverse buckling device, and belongs to the field of workover operation. The casing coupling reverse buckling device comprises a shaft body, a clamping body and a locking piece, wherein the shaft body is of a tubular structure; the shaft body is axially movably sleeved with the clamping body; the outer diameter of the lower part of the shaft body graduallyincreases from top to bottom; the lower part of the clamping body is used for being in threaded connection with the upper part of a casing coupling; when the locking piece is screwed down to enable the shaft body to axially move upwards, the clamping body is deformed by radially outward pressure and clamped on the upper part of the casing coupling; and the locking piece sleeves the shaft body ina threaded mode and is used for locking the clamping body on the shaft body after the lower part of the clamping body deforms. The casing coupling reverse buckling device can tightly clamp a casing without being lowered into the casing, and the phenomenon that a casing fishing tool gets stuck while being lowered is avoided. In addition, the casing coupling reverse buckling device provides an innerchannel for lowering an oil pipe, a tool can be lowered to fix the casing at the lower part of a reverse buckling point if the casing allows, and the accuracy of reverse buckling is effectively improved.