Abstract: After the World War II, the Japanese strategy toward the Northeast Asia changed from economic and political balance into political priority.After losing the traditional area of economic interest, the Japan actively involved in the Southeast Asia's economy and implemented the economic priority strategic toward the Southeast Asia. After the Cold War, there were a number of Northeast Asia countries rising to Japanese geo-strategic competitor, so Japan insisted the political priority strategy toward the Northeast Asia. Because there was no challenge in Southeast Asia and the status of Japan was the first in Asia and the second in the word, in order to maintain this economic statusand seek the political status which was matching the economic status, the Japanese economic cooperation in the Southeast Asia was more in political purpose——to restrain and balance in the Northeast Asia, and Japanese strategy changed from economic priority into economic and political balance.

Key word: Japan; China; Northeast Asia; Southeast Asia; economic priority; political priority