The present disclosure provides a return gas prevention device for a drainage pipe, belonging to the technical field of drainage pipes. The device realizes two functions of water seal and a check valve simultaneously, as well as prevents gas channeling in a drainage process.

The present disclosure provides a return gas prevention device for a drainage pipe, belonging to the technical field of drainage pipes. The device realizes two functions of water seal and a check valve simultaneously, as well as prevents gas channeling in a drainage process.