The invention discloses a forming cylinder transmission device of a selective laser sintering machine. The forming cylinder transmission device is mainly characterized by comprising a stepping motor, a drive gear, a driven gear, a trust ball bearing, a ball screw, a ball screw nut, a ball screw sleeve, a forming cylinder push plate, a forming cylinder, guide pillars and guide pillar guide rails; a shaft of the stepping motor is concentrically connected with the drive gear; the two sides of the drive gear and the two sides of the driven gear are symmetrically connected; the driven gear is concentrically connected with the ball screw; the driven gear drives the ball screw to rotate; the ball screw is sleeved with the ball screw sleeve; and the ball screw rotates, and therefore the sleeve is driven to move upwards, and feeding movement of powder is completed. The three guide pillars are evenly distributed on the lower face of the forming cylinder push plate. By means of the forming cylinder transmission device of the selective laser sintering machine, the size of the mechanical structure is reduced, accuracy of the sintering machine in the movement process is ensured, and stability and continuity of the mechanical structure in the transmission process can also be ensured under the situation that the large sintering machine runs continuously for a long time.