Abstract: The modern sex education in China sprung up in the early 20th century. It occurred at a time when China was increasingly influenced by the Western learning. Sex education became prosperous in the 1920s and 1930s, when a large amount of pertinent literature was published. The curricula standards issued by the educational administration ineluded sex education in it, and such courses as physiology and health education also had sex education as a part of its content. Knowledge about sex became popular in schools. Sex education was introduced to China by intellectuals who were affected by western learning. Japan was a medium in this course and educators played a crucial role in sex education. Sex education that appeared in the early 20th century is intrinsically related to the theme of the times. Independence, democracy, prosperity and the corresponding ideas of nationalism, individualism and scientism are all reflected in sex education, The initiation of discourses about sex represents the pursuit of the intellectuals for the prosperity of the nation and individual liberty.