Abstract: An automatic size-grading and shrimp peeling machine for shrimps; the automatic grading machine includes a plate-partition conveyer mounted to a slanting platform; the slanting platform is mounted with at least three conveying screw shafts coupled with the plate-partition conveyer and a plurality of feeding pipes of peeling machine. The automatic grading machine is mounted on a machine supporting frame so as to have all feeding ports mounted over the peeling machine, which includes at least three peeling units; each unit includes a large swing peeling roller and two small revolving peeling rollers; a pressing roller and at least one squeezing wheel are mounted between two small revolving peeling rollers. The squeezing wheel and the pressing roller are mounted in parallel each other, but perpendicular to the small revolving peeling rollers.