In this paper the screw extrusion principle is actually used on fused deposition RP systems. With the help of hydrokinetics principle, experiment data and design experiences, a screw extruder will be designed. Due to characteristics of fused deposition process, integrated influence of maximum press, press sensitivity and consistency, temperature adaptability, system reliability and cost, and etc. ... [Show full abstract] must be thought over in design process. A RP system with the screw extruder has been built, and its productivity increases 3∼5 times higher than else RP systems. Moreover, parts built on it have smooth surface and accurate dimensions. This system costs less than 20000US$. Maybe it is the most inexpensive RP system all over the world.