This paper proposes a new product and manufacturing technology for rapid prototyping of product systems (RPPSs). It is noted that a system in this paper is defined as a physical assembly that can be decomposed into components. The rapid prototyping is achieved by a novel modular concept, that is, the base materials to build a component as well as an assembly is highly modularised (the interface between any two modules are identical) and building a system is simply by assembling the modules. The rapid prototyping in this paper differs significantly from the rapid prototyping in literature in that the latter builds a system layer by layer and further primarily builds a component instead of assembly (building of an assembly is actually very limited with the latter, though possible). This paper explains the RPPS approach and presents a feasibility study on the RPPS technology. It has been shown that the RPPS technology is promising.