The origin and development of cities of Northeast China have a long history along with the formation of their peculiar civilization. But, before the 20th century, the level of urbanization in Northeast China lagged behind that in Central China for a long period of time due to some historical reasons. Modern cities of Northeast China originated in the early 20th century. Since the 20th century, Northeast China had gone through the immigrating and opening-up policies of the Qing government, later been invaded and occupied by the imperialist nations such as Russia and Japan for several decades. After the founding of the People's Republic of China, Northeast China has ever been the key region of China's industrialization. Today, due to economic growth and dramatic reform of economic structure, Northeast China's urban development has stepped into the rapid developing period, and been one of the regions with the highest standard of urbanization in China except for several municipalities directly under the central government, and made the great contribution to Chinese economy. Compared with other cities of China, cities of Northeast China have a special political and economic background, and clearly reflect the feature of synchronous developing and mutual promoting in the course of both urbanization and industrialization. In the paper, the authors identify the development mechanism of cities of Northeast China in the 20th century by revealing the relationships between the development of cities of Northeast China and their economic and social development. Simultaneously, the authors also analyze the historic role of the development of cities of Northeast China and some current major problems restricting their development in the course of renewing the old industrial base of Northeast China.