the theory of policy, the economic policy of Islam, normative economics.

Designing a tax system that complies with Islamic principles is one of the essentials of Islamic economics. In this regard, accommodating the Shari'a Payments in the tax system is very important. Using an analytical approach, this paper analyzes the possibility and the mechanism for replacing Khums of the business profit with aggregate income tax. The research findings indicate that, there is a relative similarity between Khums of the business profit with aggregate income tax and the possibility of their replacement. Based on the proposed pattern of this paper, the complete replacement of Khums of the business profit with aggregate income tax is not efficient, and hence a combination of Khums and taxes should be applied. In the proposed model, taxpayers have the choice between paying Khums or aggregate income tax. They will be exempt from aggregate income tax if they pay Khums of the business profit. The structure has suggestions for reforming the direct tax law and changing the executive structure of the tax administration.