The invention discloses a molding powder screening device. The molding powder screening device comprises a machine box, a feeding hopper, a first screening device, a first screen plate, a second screening device, a second screen plate, a driving wheel and a motor, wherein the feeding hopper is arranged above the machine box; the first screening device and the second screening device are mounted inside the machine box; a mounting frame is arranged inside the first screening device; a plurality of scraping bars are arranged inside the mounting frame; the first screen plate is mounted at the lower portion of the first screening device; a scraping plate clings to the upper surface of the first screen plate; the second screen plate is mounted at the lower portion of the second screening device; the outer walls of the first and second screening devices are each provided with a plurality of driving teeth which are matched with the driving wheel; the driving wheel is mounted on the motor through a driving shaft; a sliding plate is arranged at the bottom of the machine box. The molding powder screening device is capable of obtaining molding powder particles of which the size is relatively uniform, is capable of classifying molding powder and is simple to operate and high in screening efficiency.