Private banks began to work with public banks in Syria Under an economic and financial reform plan, As the public banks undertake the task of financing the public sector mainly and receive deposits from it, The private banks largely responsible for financing the private sector and increased investment in the private sector to achieve the goals of development, Although the contribution of government banks in the financing of the private sector , but it remains constrained orientations of the monetary authorities and provide support to state institutions, mainly,so, this research studied the role of private banks in the development of investment in the private sector through thevarious types of credit facilities of offered by private banks, we don't found a significant relationship between the credit offered by private banks in Syriaand the size of private investment, which means the weakness of role of these banks to increase investment, the researcher has provided a set of recommendations that will help to find appropriate solutions.