In the mechanical machining, fixture has an irreplaceable role, but in the traditional design methods for it, there are many shortcomings, the rapid prototyping (RP) technology is used in the design of fixture. The defects of fixture design were introduced at this stage, and the rationality of RP technology used in fixture design was analyzed. Then, the advantages of RP technology used for fixture design are highlighted, through the concrete example and the forming process of display.