The invention discloses a plastic tube bending device which comprises a base, support columns and a cross bar. The two side edges of the top end of the base are symmetrically provided with the supportcolumns, the cross bar is arranged between the top ends of the support columns on the two sides, the bottom end of the cross bar is provided with a sliding groove, the bottom end of the sliding groove is provided with a slider matched with the sliding groove, the bottom end of the slider is provided with a telescopic rod, the bottom end of the telescopic rod is provided with a clamping jaw, and one side edge of the bottom end of the interior of the base is provided with a motor; an output shaft at the bottom end of the motor is connected with a third rotating shaft, the top end of the third rotating shaft penetrates through the top end of the base, a fixed wheel is arranged at the position, corresponding to the third rotating shaft, of one side edge of the top end of the base, the insideof the fixed wheel is of a hollow structure, the top end of the rotating shaft is located inside the fixed wheel, and the outer side of the top end of the third rotating shaft is provided with a firstconnecting sleeve matched with the third rotating shaft; and the height of the top end of the first connecting sleeve is larger than the height of the top end of the fixed wheel, and one side edge ofthe first connecting sleeve is provided with a connecting rod, and a connecting wheel is arranged at the bottom end of the side, far away from the first connecting sleeve, of the connecting rod.