国际惯例的形成与发展是一个循序渐进的过程。它植根于参与国际交往的．行为主体的长期反复实践。早在现代意义上的民族国家尚未形成时的中世纪的欧洲，商人们在各地的大的集市上进行交易盼规则，在各种各样的地方法中几乎相同，久而久之，便形成了商人习惯法。在民族国家形成 The formation and development of international practice is a gradual process. It is rooted in participation in international exchanges. Long-term repeated practice of actors. As early as in the Middle Ages in the time when the nation-state in the modern sense was not yet formed, the merchants, trading in big bazaars everywhere, looked at the rules and were almost the same in all kinds of local laws. Over time, merchants became accustomed to law. Formed in a nation-state