Within the academic field of religious studies, the definition of religion has been a troublesome question at the core of the academic research— What is religion?— however, even today there has yet to be an accepted consensus on the issue. Nevertheless, Taiwan’s Administrative Department of Religious Affairs is forced to confront the definition of “religion” to avoid overlap with other administrative areas. To define a religion is an undoubtedly difficult business. The government must take into account religious equality, freedom of religion, separation of church and state, the principle of proportionality, public good, and public expectations. This paper discusses how the government defines a new religion in Taiwan and other countries and tries to provide reasonable and suitable suggestions.