During a long period, we cannot get a conclusion on whether Chiang Kai-shek had asked Yu Youren to send a telegraph to Chang Chi-luan and asked him to help promote “Stabbing outside must be peace first within country” or not after Mukden Incident. Through the study of the documents from the “Academia Historica” of Taipei, we can basically find the truth of this affair and the reason of the promotion of such argument of the Ta Kung Pao lies in the fear of Japanese military of Hu Zhengzhi and Chang Chi-luan.