Eojeong Songsa jeon 御定宋史筌 is a rewriting edition of Songshi 宋史 compiled by King Jeongjo and his Gyujanggak subjects in Joseon dynasty. Songsa jeon is characterized by (1) the creation of the imperial biographies of Danzong and Modi, the last emperors of the Southern Song dynasty, (2) the inclusion of Liao, Jin, and Mongol dynasties in its' biographies, (3) the creation of an independent Wuxian Biography for the five Neo-Confucianism scholars from Zhou Dunyi to Zhu Xi, and (4) the creation of Yimin Biography to honor those who had been loyal to the Song dynasty. However, it is difficult to say that the authenticity, which is one of the backgrounds of the compilation of Songsa jeon, has been fully considered. This article compares Liao Biography 遼傳 in Songsa jeon with Liao Biography in Songshi Xinbian 宋史新編 to determine the significance of Songsa jeon's compilation. As can be seen from the legend of Songsa jeon, Joseon dynasty defined Liao and Jin as 'the vulgar ethnic groups in the northeast' and 'the subject states of Goryeo dynasty', and did not recognize Mongol empire as 'authenticity' even after completely destroyed Song. In addition, Goryeo Biography is placed at the top of the biographies of the foreign states to express the criticism, and Liao, Xixia, Jin, and Mongol dynasties are arranged in the order of their founding. The characteristics of Liao Biography in Songsa jeon are as follows. First, Songsa jeon takes the form of the biography more strictly than Songshi Xinbian. Second, Songsa jeon is more thoroughly orthodox than Songshi Xinbian, including the use of Song's reign title. And in terms of content, the records of Qidan Guozhi 契丹國志 cited in Songsa jeon are basically quoted from Xu zizhi tongjian gangmu 續資治通鑑綱目. Furthermore, to express respect for Song, the Battle of Gaoliang River and the Battle of Qigou Pass, in which the Song were greatly defeated from Liao, are described very briefly. In addition, the articles from the Goryeo dynasty were recorded without omission, reflecting the position of Joseon dynasty, the bearer of the compilation. Finally, all the records on Civil Service Examination, Confucianism, and book editings are included in Songsa jeon. Its purpose is to represent the lessons. This indicates the intention that if even Liao, as the barbarian, had developed the rituals and the rites, then Joseon, as 'the inheritor of Chinese culture,' should work even harder to promote the rituals and the rites. Furthermore, considering the arrangement of the biographies of foreign states in Songsa jeon, the placement of Goryeo Biography at the top implies that Goryeo had a more advanced the rituals and the rites than Liao, Jin, Xixia, and Yuan. I think it is the ultimate intention of Joseon dynasty to express from the biographies of foreign states in Songsa jeon. On the other hand, the scholars of Qing Dynasty also tried to revise Songshi, but all of them were not completed. In this sense, the completion of Songsa jeon has historiographical significance.