"science parks are known tools for incubation of knowledge-based firms. Recently policy makers of science and technology of our country has paid attention to these institutions. The topic of this research was investigating the impact of these institutions on the development of knowledge-based companies and identifying the key factors resulting in earning competitive advantages by located firms. After reviewing many researches in this field of study key effective factors were identified and by using the experts these factors were revised according to the circumstance of our country and placed in a proper framework. The framework consists of four aspects including: “human resource” “R&D and technology transfer” “facilities” and “market development” and twelve factors. The framework applied in Sheikh Bahai Science and Technology Park and the results obtained showed that in this park facilities aspect needs special attention. This aspect had the highest significance in quadruple aspects and was the only aspect affecting Sheikh Bahai Science and Technology Park. Other aspects such as “human resource” “R&D and technology transfer” and “market development” were effects of the aspects. The results of this research show that the development of knowledge based firms located in this park depends on facilities such as financial resources and primary physical infrastructure than human resource research activities and marketing services. We suggest using this framework to find the aspects and factors influential the creation of competitive advantages and determining the action and planning priorities for other science and technology parks in Iran."