The invention discloses a machine barrel for extruding UHMWPE (Ultra High Molecular Weight PolyEthylene), and aims to solve the problems of high viscosity, poor fluidity, and susceptibility to fracture and degradation during the manufacturing process of the UHMWPE. The machine barrel of an extruder adopts a groove machine barrel; pins are arranged on the machine barrel; a copper sheathing is mounted around each pin. The extruder machine barrel provided by the invention can increase the friction between material and the machine barrel to guarantee strong forward transportation capacity, and is easy to plasticize and mix; the pins can be replaced conveniently; the copper sheathings outside the pins can achieve the functions of sealing, positioning and adjustment, so as to increase the extruding efficiency of the extruder and the mass of the UHMWPE.