Among Father Choi Yangeop’s many activities, new attention can be cast on the fact that Father Choi had great interest in history of Korean catholic church. Father Choi’s such an activity was verified in detail through his letters. After returning to the Joseon, Father Choi put a considerable amount of effort to newly understand early history of Korean catholic church. Father Choi especially had deep interest in collecting and organizing data about the martyrs. Base on those data, Father Choi wrote specific biographies of martyrs in his family, his own father Choi Kyunghwan and his mother Lee Seongrye who died in 1839. Through writing biographies, Father Choi emphasized his family’s tradition of religious belief and showed new understanding on lives of Catholics who practiced their faith in times of persecution. Above all, Father Choi tried to speak of his thought about the Catholic who were standing at the crossroads of apostasy or martyrdom. This work can be understood as pathbreaking example for writing biography of a martyr in research on history of Korean catholic church. However, Father Choi’s such an effort was neglected in further research on history of Korean catholic church by French missionaries. For this reason, Father Choi’s study on history of Korean catholic church barely had any attention up until now.