An automatic pearl screening device comprises a rack, a left side plate, a right side plate, a material bin, wherein the left side plate and the right side plate are mounted on the left side and the right side of the rack; the material bin is fixed between the left side plate and the right side plate through material bin rods, and round belt transmission systems and a recovery frame mounted at the tail part of the rack are arranged behind the material bin; a first guide groove, a second guide groove, a third guide groove, a fourth guide groove and a fifth guide groove are formed between the round belt transmission systems from front to back, and each guide groove guides primarily-screened pearls to fall into pearl long-shaft screening units via rectangular grooves in the right side plate; the pearl long-shaft screening units are mounted on the right side plate through L-shaped supports, and a long-shaft collecting frame and a short-shaft collecting frame are mounted on two sides of each pearl long-shaft screening unit and are both mounted on the rack. The automatic pearl screening device can screen the unscreened pearls to form 11 specifications of pearls, therefore, the screening efficiency is high, the implementation cost is low, the production cost of enterprises is lowered, and the efficiency is improved at the same time.