Those of the growth of e-business, the development of the cultural creative industry, the contents and knowledge industry have expanded and diversified the existing business models and created new ones. They are triggering new interpretations and discussions on business models. Such of changing business environment has paved the way for the expansion of design management within the design industry and opened new windows of opportunity for the traditionally small and non-specialized design business. Until now, the design business has not been distinguished from design industry or design service, and has not been viewed as an independent field. Rather, the design business has merely been part of a process. As such, the lack of dear definition and structured system had been a bottleneck for many design companies trying to achieve capital and social success and establish the foundation for growth and for companies striving to advance the design management in developing design business models or growth strategy in line with the changing environment. Against these sort of backdrops, this paper attempts to dearly define the design business. To this end, the paper tries to developed a design business model framework which classifies design business model into four types - customized, ready-made, provider and contract - according to the business activities between the producer and the end user, and business items into product, additional sonics, knowledge and promotion. The framework will expand the definition of design business and contribute to the expansion of design business activities and the development of diverse business models.