This Article intends to examine Stalin s role in the outbreak of the Korean War with newly released Russian documents, particularly in the historical and political context of Sino-Soviet Relations. In 1949, Stalin insisted that the unification of the Korean peninsula had to be realized in a peaceful manner. In early 1950, however, he suddenly approved North Korean War Kim Il Sung s proposal for an invasion of South Korea. The only clue to the reason for this major policy shift was found in Stalin`s telegram to Mao Zedung on 14 May 1950. In it Stalin simply stated that "in light of the altered international situation, we agree with the proposal of the Koreans to move toward reunification." What Stalin meant by the phrase "altered international situation" has remained a mystery. However, in the mid-1990s, the Russian government declassified a number of crucial documents on the Korean War. These documents illuminated the change in Stalin` view toward Korea, if not completely. By the "altered international situation" in January 1950, it suggests that thc Korean War was made possible without the direct participation of the Soviet Union. This resulted from Stalin s view about the recently established People`s Republic of China. Nevertheless the situation, in Stalin s view, was far more complex. Stalin was not entirely pleased with the victory of the Chinese Communist Party (CCP), and he was reluctant to embrace a full-fledged strategic alliance with the newly established People s Republic of China(PRC). The birth of the PRC and the signing of the Sino-Soviet alliance positively could be affect Stalin`s assessment of the balance of power in Asia and give him the confidence he need to confront the United Stated in Asia. But it is also possible to argue that Stalin perceived the rise the CCP as a potential threat to Soviet dominance of the international Communist movement. For Stalin, the success of the CCP was a double-edged sword. On the one hand, it enlarged the Soviet Union s buffer zone and helped spread Communist influence in Asia. On the other hand, once the Chinese gained military strength, they had the potential to become a rival power in the East. The Sino-Soviet Treaty of February 1950 created an important strategic bulwark for the Soviet Union in East Asia, but it also forced Stalin to abandon most if the privileges he had obtained from Jiang Jieshi in the 1945 Sino-Soviet Treaty of Friendship and Alliance. Stalin crafted a new Korea policy with these considerations in mind. Stalin cleverly manipulated the Chinese position on Korea. Stalin knew that Mao would bo opposed to taking military action on the peninsula in the near term. The reconquest of Taiwan, as Stalin was well aware, was the CCP leader s top priority. But Stalin also knew that the Chinese Communists wanted Soviet aid for the Taiwan campaign. The Soviet leader took three crucial steps to force China to consent to a North Korean military attack. First, he refrained from discussing the matter directly with Mao and instead dealt with Kim I1 Sung. Second, he asked Kim I1 Sung to inform Mao of the decision to go forward with an attack against the South. Faced with this fait accompli, Mao could only acquiesce. Finally, Stalin did not divulge any details about North Korea s military preparations and operational plans to China. The Soviet Union and China had no further discussions on Korea before the outbreak of the Korean War. In sum, The shift in Stalin s Korea Policy was intimately connected with evolving Sino-Soviet relations, revealing Stalin s complicated attitude toward the newly established Chinese Communist state. The Soviet leader certainly understood that the addition of China to Communist camp meant that the balance of power in East Asia shifted from the United States to the Soviet Union. But Stalin also feared that China s emergence as a Communist power could challenge the Soviet Union s dominant position in the international Communist movement. Stali