Controlled five-bar is an important area of contemporary mechanism. On account of the current gap in design software about five-bar, a controlled five-bar design platform (CFDP) has been developed with VC++ and OpenGL based on the theory of five-bar. The platform has two main functions of motion analysis and path synthesis, therefore offers a great convenience for the designers. This paper introduces the method of path synthesis and motion analysis, and then the functions and structures of the platform are discussed. Conclusion gives the overall attitudes on the software.