The invention discloses a plastic pipe cutting-off device capable of improving pipe material cutting efficiency. The plastic pipe cutting-off device comprises a screwed-in handle and a motor. A main shaft of the motor is connected with the screwed-in handle. The screwed-in handle is connected with an extending-and-contracting rod. The extending-and-contracting rod is connected with a driving shaft. The driving shaft is connected with a tool body. The tool body is of an arc-shaped structure. One end of the tool body is connected with the driving shaft. A plastic pipe material is put on a traction crawler belt. The traction crawler belt is mounted on a support platform and connected with a second motor. The support platform is provided with a position sensor. The position sensor is used fortransmitting a signal for detecting arrival of the plastic pipe material to a controller. The controller is connected with a display screen. The plastic pipe cutting-off device is provided with the motor, the screwed-in handle, the extending-and-contracting rod, the driving shaft and a cutting tool, and thus, the cutting tool is driven to move toward an arc locating part; and by means of the cutting tool, the plastic pipe material located in the arc locating part can be cut, and thus the fast cutting effect is achieved.