Baekje showed mature Chinese literature, such as writing poetry and literature using Chinese characters, no different from China, in the Sabi era. And document administration was thoroughly implemented. However, The period of Baekje's acceptance of Chinese characters and administration of documents cannot be specified due to a lack of related historical and archaeological materials, or it tends to be considered too late as the period of King Geunchogo, so I wrote this article to look into it. Baekje's acceptance of Chinese characters was examined through whether and when the Baekje constituent group accepted Chinese characters. Baekje was composed of the ruling class of the Buyeo and Goguryeo migrant groups and the under-dominated class of the Han tribes and Ye tribes. The Baekje ruling group split from Goguryeo, which accepted Chinese characters from the time of its founding and started document administration. The Baekje ruling group also knew about Chinese characters and document administration as the ruling group of Goguryeo at one time. Moreover, the Baekje ruling group established a site in the Han River basin after passing through the Chinese county area, where thorough document administration was implemented. The Baekje ruling group had an understanding of Chinese characters and document administration. In addition, the Han and Ye tribes, which were the dominant class of Baekje, were at the center of the Han River basin, and the Jin and Han societies, which were first located in the Han River basin, also accepted Chinese characters through the influence of Chinese residents and exchanges with Hansa-gun during each period of chaos in Chinese history, and knew or participated in the document administration of Chinese county. Baekje accepted and used Chinese characters from the beginning of its foundation because both the ruling and under-dominated groups of Baekje accepted Chinese characters. Since there was no direct record of the beginning of the administration of documents in Baekje, the beginning of the administration of documents was inferred by reviewing historical facts that presuppose the beginning of the administration of documents in Baekje. The establishment of educational institutions and the compilation of history books took place during the reign of King Geunchogo. In addition, Archaeological materials related to inscriptions from the Hanseong period are generally considered to be from the 4th century or later. This can be said to have begun the administration of documents from the time of King Geuncho's reign, as previous understanding. However, looking at the floor stone of the 道(直) name, the period of implementation of Baekje's ritual system and official ranking system, and diplomatic relations with China and counties, there is room to place the beginning of Baekje's document administration in the reign of King Goi. If we limit the period, Baekje document administration began at least from 260, the 27th year of King Goi's reign, when the official rank system was implemented. If interpreted more positively, document administration may have been implemented from the 7th year of King Goi's reign (240), when the military commander was established and the military authority of the central and local regions was reorganized. The reorganization of central and local military authority was carried out by the military command and control of all Baekje armies. This means unification of military government, and this can only be achieved through clear document administration.