After the collapse of the Cold War, international relations today is derived to a multi-polar system. Therefore, the order of the region of Northeast Asia, including the Korean Peninsula, changing to a decrease of weapons, and to improve reconciliation between countries, as a result of this transformation is obtained to the interdependence between countries. This can be said that there comes a new era of mutual assistance and cooperation in humanity. However, in ther relationship of countries in the region of Northeast Asia, including the Korean Peninsula, there is one part that does not change the structure of the Cold War. It is like the nuclear issue of North Korea, which is associated with the security situation in Northeast Asia. Four important countries, U. S. A., China, Japan, Russia have a different attitude on the issue of North Korea's nuclear and the military provocation. So, we need to understand exactly the situation of this four important countries, and have to get countermeasures to cooperate for addressing North Korea's nuclear, which is the largest disturbing for the peace and a reliable development of Korean Peninsula. In particular, Russia is one of the most important countries that can be expected on a good role in the union of Korean Peninsula. Since Russia is the strongest country in the military activities, and Energy superpower. Russia's foreign policy on problems of Korean Peninsula is pragmatic and realistic, just like the other U. S. A., China, Japan. Therefore, we need to consider the diplomatic relationship between the Republic of Korea and Russia, based on Complex interactions with other countries.