Yizhuan in Silk Manuscripts has a great deal of record of Confucian teaching which reveals the dual aspects of Confucius' thoughts in his advanced years, viz. Confucius' philosophical thought originating from his interpretation of I Ching. This paper attempts to restructure the development of the doctrine of the Mind and the Nature of Man of Confucianism in the Pre-Ch' in period. According to Yizhuan in Silk Manuscripts, Confucius says ”being benevolent and righteous is the nature of man”. The author tries to substantiate that this is the record of Confucius teaching. Confucius philosophical thought on the Way of the Heaven is so great in philosophical structure that he is unsurpassed even by his followers like Zisi and Mencius. Finally, the discussion will conclude that Confucius is the person who initiated the doctrine of the Mind and the Nature of Man.