The position of the people who participated in the Bapyo Ritual held in the reign of King Sejong and the corresponding costumes were examined. The king, who was the executive body of the ritual, wore Myeon-Bok, a court dress, and Myeon-Bok was Gujang-Bok made of Jang-wha on Guryu-Pyeongcheongwan. Crown princes, royal families, and government officials wore Oryang-Gwan and Jekraeui, which were Jobok. The crown princes' Joboks were changed from Oryang-Gwan to Wukryang-Gwan in the dynasty year 10 of King Sejong, and in the year of King Munjong's accession, Myeon-Bok was received, and after King Danjong, the crown princes wore Palryu-Pyeongcheongwan and Chiljang-Bok. Diplomats and Jongsagwan who were the envoys wore Sangbok. A Sangbok worn by the diplomat was Samo with Danryeong, Seo-Dae, and Hyeopgeum-Hwa, and a Sangbok worn by Jongsagwan was Samo, Danryeong, Heukgak-Dae, and Heukpi-Hwa. Byulgam, who served as an attendant to the king in the king's close quarters, wore Gongbok and Sangbok. Gongbok consisted of Ja-Geon, Danryeong and Heukpi-Hwa, and Sangbok consisted of orange color Cho-Rip, Jikryeong, Joa, and Heukpi-Hwa. The person holding San, Gae , Sujeongjang, and Geumwolbu wore Ja-Geon and Cheong-Ui, and Seon wore Pimoja and Hong-Ui. Siwigun wore armor and helmets equipped with weapons. Among court musicians, Aksa's costumes consisted of Bokdu, Bigongbok, Geumdonghyeokdae, Bibaekdaedae, and Opiri, and Aksaeng's one composed of Gaechaek, Bisuransam, Hyupgo, Mal, Maldae, and Opiri. As a result of the above, the process of ceremonial clothes becoming uniform clothes in the reign of King Sejong was confirmed. The king and lower-ranking officials such as crown princes, government officials, diplomats, Byulgam, armies for ceremonial weaponry, and court musicians participating in the Bapyo Ritual wore the highest grade of ceremonial clothes for each class. King Sejong had repeated discussions to build a nation based on Confucianism, and arranged each rite and corresponding costume, and the Bapyo Ritual costume was also systematically prepared for each position. The ceremonial clothing organized during the reign of King Sejong was regulated in Yejon and became the basis for continuing to the late Joseon Dynasty.