In recent decades, economic growth and development through decentralization has been the focus of policy makers, planners and researchers in the fields of economic and social sciences. Decentralization is aimed at promoting democracy and greater participation of people and local institutions in public decision-making and, consequently, increasing the productivity of public sector activities in countries. The core and one of the important dimensions of decentralization is fiscal decentralization, which is a powerful tool in controlling public sector growth and improving the efficiency of government services. With the above approach , the purpose of this study is based on explanatory - analytical method , to study the concepts and theories and study of decentralization policies , especially fiscal decentralization in Iran and Explain the interactions between financial decentralization and regional economic development and in order to achieve that , gathering data and information required in decentralization is done in library - documents and using existing resources including documents of development or pre - Islamic revolution , books , articles and research .The results of this study show that despite the increasing trend of decentralization policies and legal requirements in the development plans of the country, especially after the revolution, decentralization policies and programs have not been implemented in practice and the impact of economic decentralization on regional development has often been overlooked. Therefore, achieving regional development in terms of decentralization requires a joint analysis of the issue and theoretical consensus among planners and governments (national and regional) and provide the requirements and preconditions for the realization of decentralization with specific spatial and regional dimensions.