Abstract：English is an important tool in international communication. With the development of society, the two variants of English, British English and American English have changed significantly. There are a lot of differences between American English and British English, and the reasons for their differences lie mainly in three aspects: histories, politics and cultures. This thesis is trying to analyze the historical, political and cultural reasons leading to the differences between American English and British English, and trying to present some typical examples of differences in vocabulary, spelling and grammar. At last, it points out the significance of learning the differences between American English and British English.

Key words: American English; British English; differences; reasons; significance of study

中文摘要：英语在国际交流中发挥着极其重要的作用。随着社会的发展，英语的两个重要的变体：美式英语与英式英语，也产生了很大的变化。美式英语与英式英语之间存在着许多差异，造成这些差异的因素是多方面的，本文尝试从历史、政治以及文化三方面去分析美式英语与英式英语产生差异的原因，并且通过典型的例证，列举了英语在词汇、拼写和语法等方面的区别，阐述了其间存在的主要差异，最后论文指出了学习美式英语与英式英语之间的差异的重要性。

关键词：美式英语；英式英语；差异；原因；学习意义