Abstract: A model for the long-term software technology plan that we applied for Korean National Information Infrastructure as reviewed in this paper. Analysis and assumption on technology trends for twenty-year time frame are attempted, and application service requirements for public, economic and socio-cultural domains are identified. Based on the service requirements and technological environments of the future information society, we have categorized core sets of software technology, and have structured those technology sets into a technology tree. In the actual plan of SOFTECH 2015, each component of the technology tree was broken down into technical specifications to be utilized as inputs for the national plan of software R&D. We recognize that software technology life-cycle is becoming shorter, and many say that the life-cycle is less than one year. However, under many uncertainties, long-term plans are still required in, many instances.