Floating coupling for well cementation

The invention relates to the technical field of floating couplings, and provides a floating coupling for well cementation, which comprises a coupling body, and the coupling body is provided with a first liquid flow channel; the brittle stopper is arranged on the inner wall of the first liquid flow channel and is used for blocking the first liquid flow channel; the knocking piece is slidably arranged in the first liquid flow channel, a first tooth part is arranged at the end, close to the brittle blocking piece, of the knocking piece, and after the knocking piece drives the first tooth part to slide, the first tooth part abuts against the brittle blocking piece. By means of the technical scheme, the problems that in the prior art, when an internal driving hammer of a floating coupling knocks and blocks a glass sheet, triggering failures such as the situation that the glass sheet cannot be broken smoothly possibly occur, and therefore large construction errors are caused, and manpower and material resources are