For many people, the United States represents“ freedom and opening up”. But tracing its root back, you will find that there is also a solid Christian foundation in the United States. Then how did they step from“ sexual abstinence”to“ sexual liberation” In the 20th century, the attitude toward sex for the people in the United States changed a lot. It can’t be denied that the“ sexual liberation” also encountered a strong resistance from people who were opposed to obscenity and pornography. The author describes the rise of the sex industry and free-love culture along with relevant social changes in the United States.