The present invention relates to an automatic feeder and a feeding pipe thereof A feeding pipe (1) discharges a feed when a pig gnaws a gnawing block (12) thereon, and when the gnawing block (12) is gnawed, a pressure sensor (14) is triggered; a hopper (2) is configured to be filled with a dry feed material; one end of a spiral conveyor (3) is connected with a motor (4), the other end of the spiral conveyor is located in the feeding pipe (1), and the spiral conveyor (3) is configured to convey the dry feed material in the hopper (2) to the feeding pipe (1); the motor (4) provides power for rotation of the spiral conveyor (3); a water supply pipeline (5) provides water for the dry feed material in the feeding pipe (1) for feed mixing; and after receiving a triggering signal of the pressure sensor (14), a control unit (7) controls the motor (4) to be powered on and the water supply pipeline (5) to be opened simultaneously, and when not receiving the triggering signal of the pressure sensor (14), the control uni
