Democratic Party of Japan won the selection of the House of Representatives and became the ruling party in August 2009，and Liberal Democratic Party fell out power. This article analyzes the reasons that Democratic Party of Japan swept Liberal Democratic Party out of power，the changes in the future of Japan after Democratic Party of Japan came to power;difficult problems that the government of Yukio Hatoyama shall confront with and the unforeseeable election of House of Councilors election of 2010. Due to the uncertainty of foreign demand and depressing domestic economy，the path leading to the domestic economic resurgence is still tortuous and unfathomable. The new foreign policies of Japan will focus on the US-Japan Alliance，the foreign relationship with Asian countries and Russia.