The invention discloses a barrel which can guarantee reasonable feeding speed of raw materials. The barrel comprises a feeding section, a plasticizing section and an extruding section, and a plurality of elongated grooves are circumferentially arranged on the inner wall of the feeding section. The barrel has the advantages that after the grooves are arranged on the inner wall of the feeding section of the barrel, frictional force between a screw rod and materials entering the barrel is increased, the materials are less prone to slip, forward speed of the materials is guaranteed, and plasticizing effects of the materials are unaffected.