BYN-150 and 300 type of melon seed shelling and grading units are composed of cleaning parts and shelling and sorting parts. This unit is suitable for shelling of black, white melon seeds, hanging melon seeds, trichosanthes seeds, winter melon seeds and watermelon seeds. This unit first cleans and classifies the raw materials of melon seeds by the cleaning and grading part. After the grading raw materials are soaked, then the shelling and sorting part is carried out by the shelling and sorting part. The unshelled seeds are automatically returned to the sheller for shelling again, which greatly improves the degree of automation.