The invention relates to the technical field of spinning, in particular to a fiber cutting machine. The fiber cutting machine comprises a motor, a cutting part, a cutting disc, a power part and a cutting barrel driven by the motor. A feeding port is formed in the upper end of the cutting barrel, the lower end of the cutting barrel stretches into a cavity, and the lower end of the cutting barrel isrotationally connected with a rotating ring. A blade is hinged to the inner wall of the cutting barrel. The cutting disc comprises a first cutting cover and a second cutting cover, a first cutter isarranged in the first cutting cover, and a second cutter is arranged in the second cutting cover. The upper end of the first cutting cover is hinged to the rotating ring, and the upper end of the second cutting cover is hinged to the rotating ring. A first magnet is arranged on the outer wall of the cutting barrel. A second magnet attracting the first magnet is arranged on the power part, and thefirst magnet is used for attracting the second magnet to enable the power part to drive the first cutting cover and the second cutting cover to move in the opposite directions when corresponding to the second magnet. According to the scheme, the adhering effect of jute fibers and other fibers can be improved.