Confucianism was introduced into Vietnam from the beginning of AD. Although it initially met with resistance from the Vietnamese people, Confucianism was gradually accepted by Vietnamese dynasties and used as a national management tool for centuries, until the feudal regime collapsed. Based on the theory of cultural acculturation and ideological transformation, this study divides the introduction process of Confucianism in Vietnam into three major stages. Today, while the main basis of Confucianism exists that the feudal regime has disappeared, its effects are still persistent in modern society, dominating the way people think and act. This study focused on systematizing Confucian periods and ideology when it was introduced to Vietnam from the beginning of Christ to the nineteenth century; pointing out the regular characteristics of that process, helping readers to see the changes of Confucianism under the impact of the "localization" process.