The cost of public funds and government liquidity management have an important role in the realization of the provisions of the annual budget laws. adequate release and credit costs by executive agencies as well as the effectiveness and efficiency of the banking system (including the Central Bank of the Islamic Republic of Iran and agent banks) governments can ensure fiscal discipline and the protection of public funds. This article seeks laws and regulations related to the cost of public funds in its analysis of Iran's rights by legal approach. Accuracy in the foundations and resources, the cost stepts and critically examine are axis of this essay. Outcome of this investigation, regardless of content analysis of this issue, expressed needs, principles and guidelines for reform of the legal system governing the spending of public funds.