Tan Si-Tong, just like his contemporaneous thinkers in Chinese modern times, made his life rich and took his thought shape by assimilating Buddhist thought with his own style. As soon as he got in touch with Buddhism, Tan Si-Tong changed into a devout Buddhist, not only displaying Buddhist disposition and taste in day-to-day life, but also being engaged in Reformation Movement in Late Qing Dynasty like a Bodhisattva who is very kindhearted and merciful to save all the people in suffering and distress. More important, Tan Si-Tong established a famous Reformation philosophy named ren xue (a theory about benevolence) in Chinese modern history by merging Buddhism into Confucianism. As is known to all, because of the failure of Reformation Movement, Tan Si-Tong was arrested and killed by the goernment of Qing Dynasty. At that life-and-death moment, Tan Si-Tong met his death more like a Buddha than a hero, reflecting there being Nirvāna state in his heart.