The period of Three Kingdoms was the famous disunion era in Chinese history. The regime of Wu was not comparable with Cao-Cao in military strength and had fewer personnel of exceptional abilities than Liu-Bei. The reason why it could maintain its power and influence was the political alliance with Liu-Bei and the active deed in economy. In this thesis, the economic foundation of Sun-Wu is discussed thoroughly including its agricultural progress, industry development and commercial prosperity in order to further understand the basis of its establishment.