In this paper, patent trend on the rapid prototyping technologies is analyzed. The results show that USA has the most patents, the largest citations, and the highest CPP(Citations Per Patent) at the rapid prototyping field, and that 3D SYSTEM in USA has the most patent filings among the whole world company. and STRATASYS in USA is ranked with the highest CPP representing a technology impact in that field. It is shown that molding or bonding technology of plastic is occupied 31% by International Patent Classification Index(IPC).