The meaning of Shang ritual imagery has long baffled scholars. Art historians and anthropologists have wrestled with its meaning every since 1928 when bronzes began to be excavated at Anyang, the Late Shang capital. It is now possible to explore various data to identify the religious significance of Shang ritual art From an art historical point of view, it is evident that certain standard modes of representation were designed to symbolize the theme of metamorphosis from the human to the animal spirit realm. This symbolism also helps to explain why the ubiquitous animal image in Shang art is conceived as a mask. Epigraph-ical data support the interpretation that Shang religion was based on the belief of metamorphosis as represented in art, and that the Shang king once acted as shaman-priest, chief-in-charge of invocation and a mask wearing rite. This interpretation depends on data provided by key terms in Shang bone inscriptions, such as gui 鬼, usually translated spirit ghost and others, directly related, such as the unpronounceable ff and zhu 祝. My intention is to elucidate why spirit ghosts of ancestors, gui were envisioned as anthropomorphized animal masks and how this conception is connected with the shamanic foundation of Shang religion. Although bone inscriptional data indicates that there is a dramatic shift away from exorcistic practices of shamanic origin to cult worship focused on dead royal ancestors, the combined evidence from art and epigraphy strongly argues for a Shang religion founded on the belief in metamorphosis and the king as shaman-priest.