The North-South Negotiation of December 1911 to February 1912 was the key to success of the 1911 Revolution, and therefore this revolution can be said as ”Revolution by Diplomacy”. On the surface, the North-South negotiation was conducted by the representatives led by T'ang, Shao-i, chief representative of Yuan, Shi-k'ai, and by the representatives led by Wu, T'ing-fang, chief representative of the Revolutionaries. However, in fact, Chang Chien had played a leading role behind the scene during the North-South negotiation in 1911-1912 leading to the abdication of the Ch'ing government under certain kind of concession for the support of Yuan Shih-k'ai as the president of the republic. He had close connected with Yuan, Shih-k'ai who then controlled the Peking government, and he was also respected by the revolutionaries due to his great prestige and influence in the society and achievement in industry and in education. Of course, the success is also due to Yuan Shih-k'ai's self-consideration of his best interest to accept the presidency of the republic and Sun Yat-sen's acceptance to give up the presidency.