Abstract: A screwplasticizing 3D printing system was fabricated by designing the structures of a screw, barrel and spiral blade in this work. The pressure, velocity and shear rate were simulated by Polyflow software, and the extrusion performance of this device was investigated. The results indicated that the forced feeding could be realized by an axial force through spiral blade, and the pressure of the melt was improved with increasing rotation speed of the screw along the extrusion direction. The designed laddershaped threads favored the flow of the melt. The materials were molten by a synergic effect of shear and heat transfer within the heating appliance. The diameter of the extrudate increased slightly when the rotation speed increased from 0.1 r/s to 1 r/s.