East Asian ancestor portraits enjoyed great prominence and were valued with high esteem. For Western viewers, however, these portraits show less movement and the lack of emotional expression. While Western sitters appear with lavish interior setting, East Asian sitters are surrounded with an empty background and suggest no lively gesture. Therefore, the contrast between the natural Western style and the rigid Eastern style is obvious. Then, why East Asian portraits are so different from the counterpart in the West? It is related to their distinctive function, namely religious function. It is well known that the Western concept of fine art excludes certain types of arts in the non-West. As a result, many objects produced and used for East Asian belief systems are not artworks but artifacts according to the Western standard. The ancestor portraiture, sacred images for Confucian ancestor worship, had not been a collectable item. As functional portraiture, an aesthetic response was not normally expected or considered appropriate. It began to enjoy its high esteem as painting in modern period. On the contrary, wooden name tablets were much more important than pictorial images in the ancestor rite. From the ancient time, the Confucian rituals insisted on using wooden name tablets for ancestor worship. This wooden tablet with deceased's name is a spiritual body that symbolizes ancestor's spirits. However, they are not considered as artworks but displayed in ethnographic museums due to their non-representational form. Therefore, as Aby Warburg gained a comparative understanding of paganism in Western civilization by examining the primitive cultures, we need to apply ethnographical and anthropological approach to understand religious objects of the non-West. In order to possess better understanding of East Asian portraits, anthropological approach help us to examine these objects in a proper social context with a cross-cultural perspective.