Feudal society can be divided into the two stages of feudal lord economy and landlord economy.

Collection of water rate for agricultural use, the necessary requirements of developing water commodity economy;

Economic cooperration Integrated and The development of commodity economy of The Six Dynasties;

On Bakuhan system and commodity economy in the earlier Edo Age of Japan;

However the highly developed commercial economy changed social values and resulted in gorgeous clothing and adornment after the middle of Ming Dynasty.

This paper probes into the reasons of foreign trade development in Song Dynasty from three aspects of the development of commercial economy,the sci-tech progress and the foreign trade policy.

The commercial economy in the field of agriculture gained the great development during the Ming and Qing Dynasties sueh as grain growing,planation of the econpmic crops,husbandry,forestry and so on.

On the Development of Merchandise Economy and the Ethical Formation of Confucian Merchants in Ming-Qing Period;

The development of trade activated the rural-town economy and pushed merchandise economy, so a lot of silver from the favorable balance made it possible to use silver as circular money.

In Ming and Ching dynasty,merchandise economy in the region of Wu developed very quickly,and became more and more prosperous.