The well-known International Standard Classification of Education (ISCED 0) in China was the first edition published by 1976 (People's Education Press 1988). It adopts a three-level classification system of primary education, secondary education and higher education, and divides all levels of education from pre-school education to postgraduate education (including various vocational education and adult education) into eight educational levels. ISCED 1 is the "first level education", that is, the primary education stage; ISCED2 is "the first stage of the second level education", that is, the junior high school education stage; ISCED3 is the "second stage of secondary education", that is, the high school education stage; ISCED5 refers to "the first stage of higher education (granting academic qualifications not equivalent to the first degree of a university)", that is, the junior college level of higher education; ISCED6 is "the first stage of higher education (granting the first level degree or equivalent certificate)", that is, the undergraduate level of higher education; ISCED7 refers to "the second stage of higher education (awarding postgraduate degrees or equivalent certificates)", that is, the postgraduate level of higher education; ISCED9 is "infinite education". From the specific description of this classification standard, higher vocational education should be located in ISCED5, which belongs to higher education at the specialist level. However, with the rapid development of high technology in the world in the past 20 years, all kinds of education, especially vocational education, have doubled in form and quantity, and the first edition of the International Classification of Education has become increasingly unable to meet the actual needs. In order to adapt to the new situation, UNESCO has comprehensively revised ISCED. From the latest edition of the International Standard Classification of Education (ISCED 1997) published in March, 1997, the three-level classification system in the first edition has been greatly adjusted, and a new classification scheme of education levels has been put forward. According to the relevant description, the scheme can be represented by the following figure: the new version of ISCED divides the whole education system into seven levels. Compared with the first edition, the new edition of ISCED0 to ISCED3 remains unchanged, and ISCED4 is added as "post secondary non-tertiary education", that is, the non-higher education stage after high school; ISCED5 is still "the first stage of higher education", but it "does not directly lead to advanced research qualification". It divides the first edition into two different levels: specialist (original ISCED5) and undergraduate (original ISCED6) and "all research courses except doctoral degrees, such as various master's degrees" (original ISCED7). ISCED6 is adjusted to "the second stage of higher education" and "the qualification certificate leading to advanced research" (the doctoral course part in ISCED7); The original ISCED9, a level with uncertain connotation, was cancelled. In addition, the new version of ISCED will be divided into three types: A, B and C from the second and third levels of secondary education according to their different curriculum plans: 2A and 3A are general subject types to prepare for entering a higher level school; 2C and 3C are direct employment types, preparing for entering the labor market; 2B and 3B are intermediate types between A and C .. The fourth level is divided into A and B: 4A prepares for the promotion to the fifth level; 4B, instead of continuing to study, to prepare for a higher level of employment. The fifth level of higher education is also divided into two categories: A is "courses oriented to theoretical basis/research preparation/entry into high-tech majors" (theoretical basis/research preparation/plan to enter high-skill majors), and B is practical/technical/vocational specific plans.

Because the organizational structure of higher education courses in different countries is very different, there is no single standard to describe the dividing line between ISCED5A and ISCED5B, but it can still be roughly distinguished by several "minimum requirements". Generally speaking, the entrance requirement of 5A is a complete senior high school education (3A), and its curriculum plan "has a strong theoretical foundation" and can be linked with ISCED6; It teaches basic scientific knowledge such as history, philosophy and mathematics to meet the requirement of "having the ability to enter higher research fields", or teaches technical scientific knowledge such as medicine, dentistry and architecture to meet the requirement of "being able to enter specialized occupations with high technical requirements". As for 5B's curriculum plan, it is actually a kind of "curriculum plan for specific occupations", which is "mainly designed to obtain practical technology and specialized skills needed by a specific occupation or industry or a class of occupations or industries ―― those who pass the study are usually awarded relevant qualification certificates to enter the labor market"; Compared with 5A courses, it is "more practical and professional, and does not directly lead to advanced research courses". The academic system is generally shorter than 5A courses, but it does not exclude longer courses.

From this analysis, ISCED5B is consistent with the "higher vocational education" which is emphasized to be actively developed in China at present in terms of levels, types, objectives and courses. Therefore, higher vocational education (5B), as a specific type of "paying more attention to practicality and career specificity" in tertiary education, has a basis for classification standards compared with ordinary higher education (5A).

From the entrance of higher education, 3A and 5A, 3B and 5B can be directly connected. From the specific course content, the whole three-level course includes three different orientations: general education, pre-service or pre-service technical education and vocational or technical education. 3C, which does not lead to the fifth level, is limited to the last two levels (we can classify it as a "career-oriented course"), and 3B, which leads to 5B, also emphasizes this "career orientation" more than 3A, which leads to 5A. Because, the entrance requirement of 5B also "requires the mastery of specific subject areas in ISCED3B or 4A", which can obviously only be achieved in courses that focus on career orientation (5A has no entrance requirement in this respect). It can be seen that the enrollment of higher vocational education should be different from that of ordinary higher education, which is mainly reflected in the different courses accepted by different students in high school.

As for 3C, it belongs to high school education and direct employment, which is not the only way to enter the labor market directly. Its graduates can also enter the labor market through transitional courses in 4A or advanced training courses in 4B. For this fourth-level curriculum plan, which is between the two levels of education, the interpretation of the new version of ISCED is mainly to "broaden" the knowledge of the third-level educators, but it is generally not more "advanced" than the third level. A typical example is that some students have completed the third level education, but have not completed the courses to enter the fifth level, that is, those "preparatory basic courses or short vocal music programs" that can be included in the second level education, then the fourth level can be designed as the type of education that they are ready to enter the fifth level (4A). Of course, the course content of ISCED4 may be more professional, detailed and complicated than the upper limit of secondary education, but it also needs to meet a standard of "qualified completion of tertiary education", that is, qualified completion of any course at 3A or 3B level, or the cumulative teaching time of 3C course is at least 3 years. However, "a qualified ISCED3 course should also be regarded as the duration of the course. For example, if you have completed ISCED3 for four years on the basis of ISCED3 for two years, it can usually be considered ISCED4 ". This paper may have good enlightenment for reforming the traditional four-year secondary specialized schools in China and improving the connection between secondary vocational education and higher vocational education. After the positioning is clear, the understanding of "higher vocational education" must be the first one mentioned above, that is, higher vocational education belongs to the category of higher education, but its curriculum is special. That is, it faces the actual needs of specific occupations or occupational groups, and is more practical than ordinary higher education, reflecting the particularity of occupations; But it is also aimed at specific subject areas, unlike secondary vocational education, which can only aim at specific professional posts. Because its course characteristics are that it pays little attention to the theoretical, general and scientific principles of the subjects it studies, and it takes little time, so it emphasizes the practical application in personal career. As "vocational education" stipulated in China's vocational education law is a broad concept, it should be understood as a synonym for the comprehensive term "technical and vocational education and training" which is widely used in the world. In this way, China's higher vocational education should certainly belong to the category of vocational education. Therefore, in the above second understanding, "higher education" and "vocational education (in a broad sense)" are regarded as two unrelated juxtaposed concepts, which obviously does not conform to China's national conditions. As for the inaccuracy of the third understanding, it will be discussed in detail later.