The purpose of this study is to explore the possibility of resolving north Korea`s nuclear threat in relation to the reunification of Korean peninsular. north Korea is developing nuclear weapons and ballistic missiles as a medium to accomplish political purpose. The paper analyzes all possible military and non-military measures that can be employed for resolving north Korean nuclear issue from the perspective of crisis management. The primary requisite for denuclearization of the Korean peninsula is securing and strengthening the multilateral coordination and cooperation system among neighboring nations with the ROK-US alliance at its core against the backdrop of the United Nations` sanction regime targeting north Korea. The crisis emanating from the nuclear and missile threats by the North constitutes a single biggest stumbling block hampering the inter-Korean reunification on the peninsula. On the one hand, the crisis is a term used to describe an important cross-road situation where a patient in grave condition can be pronounced dead at the worst if something goes awry in a metaphorical sense, while on the other hand he can be recovered from illness or even be a Phoenix rising from the ashes at the best. In this regard, it is far from the stretch of imagination to assert that the removal or alleviation of north Korea`s nuclear problem, the source of all the illnesses on the peninsula, could be seen as a precursor of auspicious possibility that the situation could be evolved into the eventual reunification of two Koreas. The comprehensive analysis on the unification strategies of Germany, Yemen, and Vietnam has led to the major finding that the international environment was a key factor in attaining the unification. This implies that the linkage could be established between a various methods of maintaining pressures against the north Korea under the international coordination system and a wide range of approaches to create favorable international environment which is conducive to peaceful unification strategy through unilateral absorption or mutual agreement for achieving denuclearization or interruption of its nuclear weapons program. Ways of resolving north Korea`s nuclear issue can concretely take shape in the process henceforth. Whereas all possible military as well as non-military measures with regard to the north Korean nuclear issue should be ready in place from the stand point of crisis management, it is imperative that the door for the talks with north Korea must remain open together with coordination system involving neighboring countries. At the same time, timely communication should be proceeded through various channels in order to prevent miscalculations and unexpected behaviors from the opponent. A unification strategy was deduced from the lessons learned based on case studies of reunified nations, such as Germany, Vietnam, and Yemen. Firstly, lessons learned show that the reunification was only possible when circumstances of international community is favorable to the unification, parties concerned continue to work closely for the goal of attaining integration, and efforts are made to maximize common interests by overcoming differences of opinion throughout the entire process. In this connection, it is crucial to create favorable environment where the eventual unification could be materialized through crisis management vis-a-vis the north Korean nuclear issue in putting unification strategy of Korean peninsula in action on the ground.