One of the necessary and effective tools for economic development is the efficient bank system. In the Iranian bank system, mobilizing and allocating resources through the loans are the main function of banks. The main aim of this research is to study the mechanisms of variables such as inflation rate, liquidity, the exchange rate in the free market, economic growth rate and bank deposits amount in the banking system affect supplying loans in the banking system. Therefore, the current article aims at answering the following questions: first, what is the relationship between the liquidity and supplying loans in the banking network and also what is the between the inflation rate and other variables in loan supply? Second, how we can increase the supply of loans? The recent research studies the effects of each variable separately using the econometric technique of Auto-Regressive Distributed Lags (ARDL) for the time interval of 2010m04 to 2016m03. Also, Error correction model (ECM) is used for making a relationship between short-term fluctuations of the variables and their long-term values. The results of this research show that there is a positive relationship between liquidity, inflation rate and supplying bank loans and also, there is a negative relationship between the exchange rate in the free market and supplying bank loans. Also, there is a positive relationship between the deposits amount in the banking network and supplying bank loans.