Religion played a significant role in the Roman world in both politics and daily life. In the Roman history, many religions had gone through prosperities and declines. The mysteries was one of the interesting episodes during the religion evolutions. Mystery cults referred to the unorthodox systems of worshiping for the foreign deities, who mainly originated in the Eastern Mediterranean. After spreading in the Roman world in the first century BC, the new cults gained enormous popularity and gradually over the official religion (Scheid 2003, p.186). This essay will explore the reasons of the mysteries's success from two aspects. One is due to the needs in that historical back ground, showing by the decline of the old religion and the exposure to new cults. The other one was the advantages of the mysteries itself in terms of the unique personal experience with the deities and within the groups. More specific discussions would refer to a religious novel, The Golden Ass, written by Apuleius, which described the cults of Isis who was a goddess derived from Egypt. The decline of the state public religion in the Roman world served as a prerequisite for the rise of the mysteries. After ages that the old traditions had been taken for granted, the dissatisfaction for this boring repetitive patriotic pattern was accumulated. The intricate system of the Polytheism, believing in many gods, bothered people somehow. Paganism, the state religion, was contractual, which means giving offerings to the god in order to achieve their favours. Because of the distinctive function of each god, it usually involved numeral gods in one question, like facing a war that they were required to prayer and offer atonable sacrifice to all the deities concerned (Scheid 2003, p.154). Moreover, the observance of the religion rites became hard to motivate the citizens, since it was taken as "a public duty rather than a private impulse" (Kamm 1995, p.96). Seneca (cited in Grant, M 1987, p.158) explained why a philosopher still obey those observance that was because of the rules by the law. The truth also showed that the state religion had been taken advantage by the ruler for political purposes and even been maintained by the "coinages" (Grant 1987, p.158). Religious activities closely combined with the civic affairs that focused on maintaining the bonding of the citizens, but nothing to do with personal emotiona