Through three years of the Korean War and the strengthen role of the Cold War system, China and North Korea determined to build a relation of allicance in the form of mutual asistance in the early 1960s. During the Cold War, Sino-Korean alliance had its characteristics of the era and it brought a security guarantee and practical interests to maintain the geopolitical and military balance in Northeast Asia. Since the end of the Cold War, China-DPRK realations have not been so stable because of the influence of international political situation changes. With the escalation of the nuclear issue and the development of China-ROK relations in recent years, Sino-DPRK allicance basis which was “sealed in blood friendship” has been questioned. Is it to continue to consolidate the alliance and to develop the all-round cooperation partnership, or to repeal the treaty of alliance and return to a normal state relations? The decisive factor still lies on the national security and practical interests. Under the influence of the current international situations, the historical ambiguity will continue to maintain in the alliance between China and DPRK.