The functions of the intellect - which is one of the topics raised in the field of epistemology - are the activities and effects that the intellect performs in acquiring knowledge and recognizing objects and facts. The purpose of this research is to know the various functions of philosophical intellect and their application in the births and innovations of Islamic philosophy. This article has been made using analytical and argumentative strategies and document methods, logical and syllogistic analysis. The functions of intellect in philosophy should not be considered exclusive to its argumentative function. Philosophical intellect has various functions, and in order to know the differences of Islamic philosophy from other philosophical schools and to continue the growth of Islamic philosophy, we must pay attention to all these functions. The functions of philosophical intellect include imaginations perception, finding universal concepts, dividing concepts; combining concepts; making new concepts; building coherence between related objects, imaginations or affirmations; to affirm; questioning; description; explanation; interpretation; analysis; reasoning; ideation; theorizing; And the criticism that the application of the mentioned functions in Islamic philosophy has led to many births, such as the presentation of some divisions of existence by Islamic philosophers, the conceptualization of the perpetual origination by Mir Damad, the presentation of the problem of mental existence byFakhr al-Din al-Razi, a new reading of Plato's political philosophy by Farabi, the analysis of how existence Generalities by Avicenna, evidences proving the originality of existence, the supreme spacious of energy by Allameh Tabataba'i, Suhrawardi's illuminated metaphysical theory, etc.