As a Jesuit priest dispatched to the Qing Dynasty, Father Régis, by order of the Kangxi Emperor, led the production of the Huangyu Quanlantu (皇輿全覽圖), China's first map from original survey survey. Through his observations and research during visits to various regions, Régis documented the local customs, religions, ideologies, institutions, and history in reports. Among these was a report concerning Korea, a portion of which constitutes ‘An Abridgment of the HISTORY of COREA,’ describing Korean history in a form of synoptic history. ‘An Abridgment of the HISTORY of COREA.’ is a valuable historical source that significantly broadens our understanding of key issues in ancient Korean history, such as the starting point of Korean history and the location of the Lelang Commandery. However, this source has been rarely utilized in Korean ancient history academia. Maybe this is due to the absence of critical review. To solve this problem, this paper undertakes a thorough critical examination of ‘An Abridgment of the HISTORY of COREA.’ The findings suggest that Régis employed a considerable level of historical criticism when referencing historical accounts of ‘Corea’ recorded in Chinese official histories. To be Specific, it appears that Régis, utilizing his proficiency in Classical Chinese―sufficient to interpret The Book of Changes (周易), his historio-geographical knowledge of China and its surrounding regions gained during the production of the Huangyu Quanlantu, and his research on Chinese official records, established the ethnic and spatial boundary of ‘Corea’ as it changed over time. Subsequently, he meticulously reviewed Chinese official histories to ascertain whether there are records aligned with the boundary and whether these records were suitable as historical evidence for his narrative in ‘An Abridgment of the HISTORY of COREA.’ Although inevitably influenced by a Sinocentric historical perspective as a French missionary dispatched to the Qing dynasty, Régis employed what was, for the 18th century, a highly advanced historical methodology - a philological and empirical modern historical approach - to describe Korean history in a synoptic form. Therefore, it seems reasonable to acknowledge that the ancient history section of Régis's ‘An Abridgment of the HISTORY of COREA’ can be regarded as a considerably reliable secondary source for the study of early Korean and Chinese history. This point offers the Korean historical academic community, particularly those specializing in ancient Korean history, several significant implications.