Shendu is an important part of Confucian cultuire and an indispensable method of Confucian selfcultivation system. Shendu is often understood as self-discipline in privacy, but the tracing of the theory reveals that the real meaning of Shendu is sincerity and concentration, an inner rather an exterior concept. The theory that human is an integral part of nature is the ideological background and transcendence basis of Shendu. Following the inner thoughts and concentration is consistent with the basic contents and methods of Shendu. The objective laws of external manifestation of inner ideas and the subjective pursuit of internal saints and external kings endow Shendu with indispensable practical value. It is just because Shendu has complete theoretical support and important practical significance that the thought has gained endless vitality and become the cultivation realm for Confucianists to vie to achieve during the past thousands of years