An intelligent design software system for the power station pipe-prefabrication (PPDS) has been developed in the paper, which is taking pipe material database as core and developed on the platform of AutoCAD and Borland C++.Whereas design and construction of power plants in China belong to different departments, the input and recognition problem of pipeline system disposition chart must be solved firstly for the prefabrication design. Based on AI technology, the model fast building subsystem (MFBS) was established for entering the 3-D pipeline graph data, so that the problems of reconstruction of pipeline digital model and computer identification of original 2-D design data can be solved. The optimization design scheme in the pipe-prefabrication process has been studied and also the corresponding algorithm put forward. The technique and system mentioned can effectively raise the pipe- prefabrication design quality and efficiency in the construction of large scale power plants, reduce the period of design and the waste of raw material. PPCADS has still offered the functions such as the construction design for pipeline prefabricated process, the detailing drawing for manufacturing pipe section and automatic generating the technical files for the completed project.