In order to meet the demand of American social development in the 20th century for talents with certain cultural knowledge and skilled skills, redefining the educational function of American middle schools has become an urgent problem. 19 18, the "American Secondary Education Reorganization Committee" put forward a report entitled "Basic Principles of Secondary Education". The report summarizes the functions of secondary education as follows: to cultivate students' health, master basic methods, have professional skills, have citizenship, be noble family members, enjoy leisure properly and show noble moral quality. The report also puts forward suggestions for the reform of the academic system: 6- 12 years old is the primary education stage, and 12- 18 years old is the secondary education stage. The secondary education stage is divided into two parts, and the study time is 3 years each.

In the 1940s, while continuing to emphasize the cultivation of students' civic responsibility, American secondary education paid enough attention to the cultivation of students' professional ability. In 1944 "Education for All American Youth" issued by the American Education Policy Committee, vocational education was placed at the top of 10' s requirements for American youth.