We read in the PhD dissertation on the economy that financial part has always been the main focus of the subjects under study. The main reason for paying much attention to this subject is the central role of the financial part to the economic development and growth. An importance of the development of financial markets for economic growth is regarded in the PhD dissertation on the economy, which is a key subject of the development economy. With regard to the importance of these subjects, the study of the relationship between financial development and economic growth in the PhD dissertation seems to be essential and necessary. In this dissertation, we shed light to the effect of financial development, commercial ratio, domestic investment and the interest rate on the economic growth. The main goal of this dissertation is to answer the question regarding the effectiveness of the financial development on the economic growth. After studying this objective and answering this question in the results of the Ph.D. dissertation, other variables including investment, interest rate, and the commercial index would be addressed. A certain period of time is selected in the dissertation to study the relationship between the variables. Also, in this dissertation, Auto Regressive Distributed Lags method (ARDL) is normally used in order to study the results. Results of the current dissertation indicate a positive significant relation between interest rate and domestic investment with economic growth. Short-term demonstration of the positive and significant relationship between financial development index and economic growth is also discussed in the PhD dissertation on the economy.