Proclus is one of the most important Neoplatonists who lived in the fifth century BC. He is among those who devoted themselves to systematically compiling and explaining the Neoplatonist system and worldview. The main problem of Proclus is the same as that of Plotinus and other Neoplatonists, namely, research into how plurality arises from unity. Like Plotinus, Proclus accepts the theory of means in the relationship between unity and plurality, but offers a different interpretation of it. Although Allamah Tabataba'i is also one of the prominent Sadr philosophers, he has nevertheless proposed new perspectives in various theological fields as a result of his deep reflections on the verses of the Quran. The issue of the relationship between the one and the many is one of the prominent points of his thought, which he has explained by relying on the one and the attributes of the one. The present article attempts to compare the ways in which the problem of the relation of the one and the many is solved with respect to the one and the characteristics of the one in the intellectual systems of Proclus and Allama Tabataba'i, while examining the characteristics and attributes of the one in the intellectual systems of these two thinkers.