Cheng-tung Hsing-sheng(征東行省) was established for the first time in Goryeo and southern China right before the second conquest of Japan by Mongol in 1281, and then both were abolished after the failure of the conquest. Later, as Mongol resumed the preparations for the war, it was set up again in two places in 1283, and while the Hsing-sheng in the southern China was exclusively responsible for the actual preparations for the war, that in Goryeo was exempted from the burden. Then, as the conquest plan was canceled, the Hsing-sheng in the southern China was closed in May, 1284, but the one in Goryeo was maintained. It’s because the Hsing-sheng in Goryeo controled Jinbyeonmanhobu(鎭邊萬戶府), which had been established right after the failure of the second conquest, rather than participated in the actual preparations for the war, and took on the new mission to defend the southeast coast from Japan’s counterattack. Later, as the preparations for the war were resumed in 1285, it was given the role again to procure soldiers, vessels and weapons with the Hsing-sheng in the southern China, and was still maintained even after the Hsing-sheng in the southern China was discontinued. Therefore, it’s difficult to accept the general opinion that when King Chungryeol was appointed as the Haengsangseoseong(行尙書省) Pyeongjangjeongsa(平章政事) in May, 1287, Cheng-tung Hsing-sheng appeared in Goryeo with new features not related to the conquest of Japan. Hsing-sheng already existed at that time, so it's just the result of the change in the name and the position of its minister due to the reform of Mongol government organization enforced just in time. Later, Cheng-tung Hsing-sheng once concentrated on the suppression of the Nayan and Qaidu rebelling forces, but didn’t abandon its role by actively cooperating the preparations for the conquest of Japan that began again in 1293. When the successive regime following that of Khubilai withdrew the plan for the conquest over Japan totally in January, 1294, with his death, it was exempted from the duty of the conquest of Japan, so its character came to be changed at last.