Abstract: The period around the Hundred Days Reform witnessed the transition of intellectuals’ mentality from collapse to reconstruction in the late Qing Dynasty, for which Buddhism had provided important mental support. SUN Bao-xuan’s Diaries in Wangshan Cottage provides informative records of intellectuals’ rising interest in Buddhism, the confrontation between political and cultural thoughts and Buddhist ideas, and the relations between Confucianism and Buddhism in the adjusting process of Confucianism. It also shows that at the metaphysical level, when the philosophy discipline was initially established in the late Qing Dynasty, the combination of Buddhism with the doctrine of mind in ancient China and philosophy and psychology in the West led to a “new view of the world” in a strong Buddhist tune, taking a “schema of mind and things” as the core. As for the social and political thought, the study of Gongyang was central to New Text Confucianism and also functioned as the ideological foundation of the Hundred Days Reform. The Diaries provides informative records about the popular topics of that time such as “three religions and three lives” and “future pure land”. The influence of Buddhism on the study of Gongyang in the late Qing Dynasty enriches the theoretical connotation of the Hundred Days Reform and strengthens the political belief that human beings’ spirit can save itself.