Abstract: There are three characteristics in modern company system，ie．，legal person， partnership，and the separation of capital ownership and capital operation．All of these elements had been initially fostered in the medieval western Europe．The guild in the Middle Ages had embodied a series of“elements”of company， such as group identity，concentration of economic power，the ideas of cooperation and sharing; the merchant of medieval Italy had constructed the primary form of modern company， including the social partnership， the family partnership and the family company; the regulated merchant company in medieval England had many features of modern company，and on the base of these companies started the course of transformation to joint－stock company．

Keywords: medieval western Europe; guild; Italian company; regulated company; joint－stock company