For developing countries to catch up, it is vital that they develop emerging technologies and the system that supports that development. The literature suggests developing a technological innovation system (TIS) framework to investigate the development of technologies in a country. Nonetheless, most of this research focuses on developed countries without taking into account developing countries. Therefore, in this paper, we have two main goals. First, reviewing the indicators introduced to the functional analysis of TISs and modifying these indicators based on developing countries' circumstances. Second, applying this framework to the specific case of Iran's renewable energy program by using these indicators for analyzing Iran's photovoltaic TIS to identify the problems. Accordingly, we review indicators used for a functional analysis by considering the needs of developing countries, and we propose a list of indicators that can be used for assessing functions in developing countries' TISs. The results show that, to evaluate some functions of TIS, we need to use new indicators in developing countries. Finally, we propose some policy recommendations to tackle these functional problems.