Reducing connecting device for water supply and drainage pipe

The invention discloses a water supply and drainage pipe reducing connecting device, and relates to the technical field of drainage pipe connection, the water supply and drainage pipe reducing connecting device comprises a connecting pipe body, the inner wall of the connecting pipe body is slidably connected with a first sliding block, the top end of the first sliding block is hinged with a first connecting rod, and the top end of the first connecting rod is hinged with a fixing block; a sealing rubber pad is fixedly connected to the top end of the fixing block, a sealing assembly is arranged at the bottom end of the connecting pipe body, the water pipe body can be guided through the arranged guiding plate, when the water pipe body makes contact with the guiding plate, the guiding plate can be extruded to move backwards, the guiding plate drives the fixing block to move backwards, and the sealing assembly is arranged. The fixing block can drive the first connecting rod and the second connecting rod to move in