Abstract：With the development of the international trade, the use of letter of credit is also becoming increasingly common, especially the Irrevocable Credit. Since Jan 1st, 2007, The International Chamber of Commerce, ICC has redefined the letter of credit in Uniform Customs and Practice for Documentary Credits 600 (UCP600). The revision of UCP600 means that under the new provision the Credit will be automatically composed of irrevocability when issued by banks. Concerning the effect of this change in international trade, the author decides to carry out a study centering on “The Function of Irrevocable Credit in International Trade”. By implementing such a study, the author hopes to find out the specific impact of this change.

　　　The theory of this study will subject to the comparison between Revocable Credit and Irrevocable Credit. By involving to this area, the author hopes to allow more people to be familiar with Irrevocable Credit and understand as well. 

Key words: Irrevocable Credit; UCP600; Function; International Trade

中文摘要：随着国际贸易往来的增多，信用证的使用也越来越普遍，尤其是不可撤销信用证。2007年1月1日，国际商会在《跟单信用证统一惯例第600号文件》里对信用证的定义做出了重新的修改。这一修改意味着在新的规定下，信用证一旦由银行开出后，都会自动带有不可撤销性。这一改变不多不少都会对国际贸易带来一些应向,在此,笔者以“不可撤销信用证在国际贸易中的作用”作为本论文的主题，希望借此来分析这一改变的具体影响和表现。

　　　本论文主要以可撤销信用证与不可撤销信用证的比较为媒介来对论文主题进行阐述和研究，并希望通过对此方面的涉及让更多人熟悉和了解不可撤消信用证。

关键词：国际贸易；不可撤消信用证；国际商会；信用证