This paper tries to identify and compare the levels and frameworks of innovation systems (IS) approach. Innovation systems approach is a new approach to innovation and technology development that developed and evolved in the recent two decades. This approach is a systemic approach to innovation. Consisted of three parts, part one tries to identify and analyze the existing different analytical approaches of Innovation systems, the second part focuses on knowledge, types of knowledge, interactions between knowledge and nature of generating and using of knowledge as the base of innovation, and the third part compares three main frameworks of innovation systems from knowledge perspective to recognize differences of the mentioned frame works.