This research investigated the awareness on the ‘boundary’ of Goryeo focusing on the awareness on succession of Goguryeo and northern territory awareness. Succession awareness of Goryeo on Goguryeo revealed distinction from the surrounding powers that stood against concentration of regional power by claiming legitimacy of dynasty in the confusion of Namalryeocho. Since its foundation, Goryeo implemented ‘Yanggyeongje’ by installing Seogyeong in Pyeongyang simultaneously with relocation of capital city to Gaegyeong. ‘Yanggyeongje’ of Gaegyeong Seogyeong connected foundation of Goryeo and succession awareness of Goguryeo. Seogyeong, an axis of Yanggyeongje, greatly influenced northern territory awareness simultaneously with succession awareness of Goguryeo on Goryeo. This point was a background to overcome the first war with Khitan, on the other hand, it was a cause of territorial conflict with surrounding nations. Territory awareness of Goryeo included the territory of unified Silla and old Goguryeo, and northern Yalu river was the center of outside ‘boundary’ awareness of Goryeo. The situation of northern region of early Goryeo was an opportunity to actively progress northern policy that Goryeo aimed for, however there was a possibility to create a territorial conflict with northern people. Active construction of fortress against northern region since foundation of Goryeo was a basis to extend northern territory awareness of Goryeo. ‘Yanggyeje’ was an institutional device to maintain this, and this acted as a local system equal to military system and 5 Doje to protect capital Gaegyeong from northern region. Northern ‘territory’ awareness of Goryeo was gradually extended to Yalu river through construction of fortress that began from the early Goryeo. Conflict with northern people was involved in the process. Goryeo and Khitan constructed fortress respectively in ‘Gangdong’ and ‘Gangseo’ mainly with Yalu river through reinforcement negotiation during the 1st invasion of Khitan. At this time, territorial division between ‘Gangdong and Gangseo’ at the boundary with Yalu river became more reinforced while overcoming the 2nd·3rd war with Khitan. As the result, ‘Goryeo-Jangseong’ was constructed in 1033(King Deokjong 2nd year), and Goryeo Cheonhagwan of ‘Hwanae Hwawe’ was established based on this. Division of Goryeo and foreign people into ‘Hwanae Hwawe’ was an extended territory awareness from the territorial boundary division of ‘Gangdong Gangseo’ based on Yalu river, previously. In conclusion, awareness of Goryeo on northern ‘boundary’ secured identity of territory awareness through Goguryeo succession awareness, and was firmly established based on territorial division into ‘Gangdong Gangseo’ and establishment of Cheonhagwan of ‘Hwanae·Hwawe’.