In Vietnam, Catholicism is a religion that is very sensitive to the national and international situations. The changes made by Catholicism itself or caused by the situation in Vietnam and the world have impacted more or less on the current sustainable development in Vietnam. This paper focuses on the changes of Catholicism taking place since 2004, when the Standing Committee of the 11th National Assembly enacted the Ordinance on Beliefs and Religions on the 18th of June of the year. In addition to a number of resolutions and instructions, such as Resolution No.24-NQ/TW on strengthening religious affairs in the new situation dated 16 October 1990 and Resolution No.25-NQ/TW on religious affairs dated 12 March 2003, the promulgation of the ordinance on beliefs and religions is seen as an important factor affecting changes of the Catholic Church in Vietnam. In this paper, the changes of Catholicism are reviewed in the political, cultural, environmental, and socio-economic aspects. Both positive and negative impacts caused by the changes on sustainable development in Vietnam are analysed.