In his later life, the distinctive feature of Sikong Tu's inner world was a combination of the teachings of Confucianism, Buddhism and Daoism with the latter two serving as his major spiritual support that allayed his deep resentment and fear and eventually brought peace and aworriless mood into his mind. By analyzing his great ambition in his early years, and the influence upon him by his association with Wang Ning and Lu Xie, as we as his change thought in his later life, the authors of this article seek to penetrate and to explore the close relationship between Sikong Tu's line of thought and his religious belief so as to provide evidences for future study.