In this paper, with a novel approach, authors are trying to develop an analysis framework to promote IT innovation system by synthesizing terminologies, reference models and theories from Enterprise Architecture discipline and Innovation System Theory. A mixed method research (Qualitative/Quantitative) has been applied to develop and empirically use of the framework. In the first step, through a qualitative method, using expert interviews, we conceptualised this framework. Then in the second step, a survey research has been conducted to explore the instititutional model of IT diffusion as a part of the framework in a given country (Iran). The results show that we may apply this framework in policy making and analysis of IT diffusion and development at the national level in forms of a framework and an institutional Model (list of institutions). It has been also shown that this framework can be an multi-faceted integrated tool by which we could extract and analyze different models on various dimension of an innovation system.