Anti-overflow drainage device

The anti-overflow drainage device comprises a first connecting pipe and a first threaded head in threaded connection with the interior of the first connecting pipe, a drainage pipe is fixedly connected to one end of the first threaded head, an overflow opening is formed in the drainage pipe, a second threaded head is fixedly installed on the first connecting pipe, and the second threaded head is fixedly connected with the first connecting pipe. A first baffle is installed on the first connecting pipe in a surrounding mode, and a second baffle corresponding to the first baffle is fixedly installed on the drainage pipe. Through the installed first connecting pipe and the first threaded head, when the anti-overflow drainage device is used, after the sealing ring is arranged on the drainage pipe in a sleeving mode, one end of the drainage pipe is inserted into a hole groove preset in a bathtub, and the first connecting pipe and the drainage pipe are in threaded connection through the first threaded head; furtherm