An irrigation and drainage device connected to an adapter tube is disclosed to include a device body having an irrigation connection hole in communication with an irrigation control chamber, a drainage connectiOn hole in communication with a drainage control chamber, an ilTigation mounting hole with a bottom opening, a drainage mounting hole with a bottom opening, a communication hole in communication between the irrigation mounting hole and the drainage mounting hole and an adapter connection hole connected to the adapter tube and controllable for communication with the irrigation mounting hole, the drainage mounting hole or the communication hole, an irrigation control device including a linked rod movably mounted in the ilTigation mounting hole, a valve flap connected to the linked rod for sealing the ilTigation mounting hole, and a drainage control device including a linked rod movably mounted in the drainage mounting hole, a valve flap connected to the linked rod for sealing the drainage mounting hole.
