Common financial Engineering is a set of sciences or techniques that seek to find new and effective ways to provide optimal funding in the institutional framework of a System governing liberal economics. The main question is whether it is possible to achieve the goals and strategies of the Islamic financial System by simulating them. In order to get the answer, the article first describes the historical and functional course of current Islamic finance and its analysis and pathology. The prevailing approach of Islamic finance is the common passive method (adaptation, simulation, and correction), the common denominator of which is the emphasis on the reconstruction and signing of the achievements of Marginalismin the financial economy. Research at this level, by employing the System of jurisprudence, lacks a specific methodology in line with the objectives. In addition to the problem of lack of consensus on financial issues, the passive approach is associated with risks such as compliance and lack of coordination of components, widespread use of hail, complexity, which in general causes the uncertainty of contract rules and the philosophy of usury. And other certain rules have been applied to transactions. This approach led to the opposition's ridicule and the Islamic Republic's failure to distinguish the common from the common. It is suggested that in the first step, with the approach of Systematization and the idea of moderation of jurisprudence, to discover the economic economy from the interests of jurisprudence and ethics and within its framework and in accordance with the goals of patterns, tools and institutions of Islamic financial System to meet real financial needs.