Worldview as a kind of man's look towards the world of reality has a severe influence on his classification of knowledge. In other words one may see in classification of knowledge the unity as well as plurality. This article deals with the fact that how classification takes place in man's epistemological process. Perception and epistemology are mentioned as the key points here. Philosophers are usually classifiers and their point of views forms the way they classify things and concepts. Relationship and how one looks at it in shaping the classification scheme is critical. The classifications which have been introduced up to now have had several models. They represent the kind of looking at, or point of view of their founders to the world. Aristotle, as a philosopher as well as an encyclopedist, is one of the great founders of knowledge classification. Afterwards the Islamic scholars followed him while some few rejected his model and made some new ones. If we divide all classifications according to their roots we may define them as human based classification, theology based classification, knowledge based classification, materialistic based classification such as Britannica's classification, and fact based classification. Tow broad approaches have been defined in this article: static and dynamic. The static approach refers to the traditional approaches and the dynamic one refers to the eight way of looking toward objects in order to realize them. The structure of classification has had its influence on epistemology, too. If the first cut on knowledge tree is fully defined, the branches would usually be consistent with it.