Since World War II ended, the United States of America has been known as one of the greatest powers in our world. The USA has various kinds of relationships with other countries, as for instance the United Kingdom, China. In my thesis I am concerned with the relationship of the US with East Asia, more specifically China. Studying US-Chinese relations during the first half of the 20th-century makes it inevitable to introduce one of the most influential policies during the first half of the 20th-century, namely “the Open Door.” This study is going to give you a short review of how John Hay’s idea of equal rights on the Chinese market has changed throughout the years under his successors and become something far different from Hay’s original expectations.