Choi Chang-hyeon was a leader of Roman Catholicism from the foundation of Roman Catholic Church in 1784 to the Shinyu Persecution of 1801. He made a big contribution to the development of Korean Roman Catholic Church in the late 18th century. He was the priest of the laity and general catechist. He translated Sung- Gyeong-Jik-Hae and led Fr Zhou Wen-mo to Joseon. At the end, he died as a martyr. Therefore, a story of his life is a personal history and history of Korean Roman Catholic Church in the late 18th century. He was born in yeokgwan (an official interpreter) family in 1759. He worked at a drugstore to help his father. In 1784, he entered the church because of recommendation by Lee Byeok. At that time, he studied with silhak (practical learning) scholars of the Namin faction including Lee Byeok and, as a result, became a Roman Catholic. As a member of the middle-class family, in addition, he was open- minded about new culture. In addition, he was aware of the limitations of Joseon’s rigid caste system, and there was a sinner in his family. Therefore, he decided to become a Roman Catholic. In 1786, he was appointed as the priest of the laity and administered the sacrament as a father. He devoted all his energy day and night for other fathers and associates. Since the Shinhae Persecution, he led the church and invited Father Zhou Wen-mo into Joseon. As the general catechist, he took care of all church affairs, copied books for believers’ religious life and translated Sung-Gyeong-Jik- Hae into Korean. He formed a human network with believers in various fields including his relatives Choi In-gil and Choi Phil-je and developed Roman Catholic Church in cooperation with these people. With humble and moderate personality, he was the most respected person in the church. He was arrested in January 1801 and became an apostate. However, he kept silent about the hideout of Korean Roman Catholic Church and his followers. Later, he regained his faith and was decapitated at Seosomun on February 26, 1801. In the middle of studying his activities, this study has been able to find out the followings; renaming laity hierarchy to pseudo-hierarchy, ten fathers nominated by Lee Seung-hoon, the gathering place of the priests of the laity at that time and relevance between the Jeongmibanhoe Incident of 1787 and the priest of the laity.