Abstract: This article discusses how the American character shapes the American English vocabulary. Based on the descriptive research and analysis of the foreign words introduced into American English, the article aims at further revealing the relationship between American culture and the American English. At the age of globalization when American English is becoming so popular, the research is helpful to enhance understanding of American culture and language. The author points out that the American strong tendency to embrace and absorb foreign cultures enables the American people to import numerous foreign words into their language, which helps enlarge the American English vocabulary and enrich the expressions of the American people. The American spirit of innovation meanwhile leads to the reforming of the American English vocabulary, making it new and different from the British English vocabulary.