Human mental dimension consists of three aspects of epistemology, emotion and volition. Affection is one of the most important components of emotional aspect of the soul. This article explains the status of affection in the areas of the soul and studies its mechanism of influencing human function, especially in human ascending to ultimate perfection as viewed by Allameh Tabatabai. Allameh has a special concern of the effects of human needs and feelings on human epistemic realm, a concern which distinguishes his analysis of the effect of affection on the final issue of one`s function. From his point of view, affection is an existential truth and tendency to perfection found in all beings. Its full degree, however, appears in human being. Since various things are taken as objects of human affection, it take different forms as positive, negative, imaginative, and rational types; given the object of human affection to be a perfect and spiritual object, the affection would be positive. This affection as a true leader leads man to his true perfection. Harmonizing perfectional movement of other human aspects of existence, affection would lead them to its full degree of perfection. On the other hand, with the help of reason, he leads the individual to a transcendental purpose, and the master of the perfect path leads the way to the true and perfect perfection through the establishment of a connotation with him.