This article deals with Li Erqu's philosophy and his perspectives toward Confucianism, Buddhism, Taoism. Based on Li's letters, the another tries to review the discussion between Li Erqu and Gu Yanwu. By doing so, we may clarify ”Ti Yong”. Also, Li Erqu indicated that ”Ti Yong” was originated by the sixth Chinese Zen Patriarch Hui Neng. Thus by comparing Li Erqu and Hui Neng's expression about ”Ti Yong”, we may achieved a comprehensive understanding of their thoughts on this topic.