This essay looked into the change of international situation and patterns of the foreign policy of the koryo dynasty in Northeast Asia between 10th and 13th. The summary of this essay is as follows. Firstly, the Manbugyo(萬夫橋) case that is understand a foreign policy of Taejo Wang Geon(太祖 王建), the founder of the Goryeo Dynasty is hard to judge a proper political action. And it is also difficult to understand ina viewpoint of national interests. The action of Taejo was an immediate opposition to proposal of the other nation. It signified that he had adopted a hardline. Secondly, the meeting between Seo Hee(徐熙) and So Sonnyeong(蕭恒德) is regarded as a model of diplomacy. It was a practical policy and an important indicator in subsequent foreign policy. The foreign policy of Seo Hee and Songjong(成宗) is earning many positive reviewsthat it was maintained peace and was extended the border to the extent of the Amrok River(鴨綠江). It will havehighly praised as good foreign policy for peace and co-existence. But it will have criticized that lost independency. Thirdly, after Goryeo repulsed the Kitan in 1019, Three Kingdoms in Northeast Asia kept the peace. But it did not derive from similar military power. In the situation of Northeast Asia from the late 10th century to the early 11thcentury, the going north of the Song and Goryeo was frustrated by Kitan with strong force. As a result, the Song dedicated an annual tribute to Kitan for defense the border. And Goryeo treated Kitan with the utmost courtesy. Fourthly, when the Jurchens appeared, the Song and Kitan had not aggressive offensive. It seems that they promoted reversal through the medium of Goryeo. But they could not get any help from Goryeo. Under the difficult circumstances, Goryeo also had little influence. They did not maintaina solid friendship with the other nation, and became the oppressed people. Finally, the military regime of Goryeo in the first half of the 13th century did not know about information and reality of Mongol, the newly rising a supreme ruler. As a result, Goryeo had not responded adequately to the diplomatic negotiation with Mongol, and had been occupied by Mongol empire.