Primary industry refers to agriculture, forestry, animal husbandry and fishery (excluding agriculture, forestry, animal husbandry and fishery specialty and auxiliary activities). The secondary industry refers to the mining industry (excluding mining specialty and auxiliary activities), manufacturing industry (excluding metal products, machinery and equipment repair industry), electricity, heat, gas and water production and supply industry, and construction industry. The tertiary industry, i.e. the service industry, refers to other industries besides the primary and secondary industries, mainly including transportation, communication, commerce, finance, education, catering, and vocational services.

Because the tertiary industry includes many industries and has a wide range, according to the actual situation in China, the tertiary industry can be divided into two major parts: the first one is the circulation sector, and the second one is the service sector, which can be specifically divided into four levels.

The first level: circulation sector, including transportation, post and telecommunications, commercial catering, material supply and warehousing. The second level: the production and living services sector, including finance, insurance, geological survey industry, real estate, public utilities, residential services, tourism, consulting and information services and various types of technical services.

Third level: sectors serving to improve the level of science and culture and the quality of the population, including education, culture, radio and television services, scientific research, health, sports and social welfare services. The fourth level: sectors serving the needs of social public ****, including state organs, political party organs, social organizations, as well as the army and police.

The status of the three major industries in the national economy:

1. The primary industry is the foundation of the national economic development: as the primary industry of agriculture, it can provide the most basic material foundation for the development of the country and satisfy the people's normal living needs.

2, the secondary industry can promote the rapid development of the national economy: with the material foundation as a guarantee, the secondary industry was created, through the major mineral resources, oil and other types of resources to develop and utilize, can drive the development of the primary industry, to improve the country's economic level.

3, the tertiary industry for the primary industry, the secondary industry services, promote the progress of the primary and secondary industries: the tertiary industry is the primary industry, the secondary industry is complementary, can serve. The accelerated development of the tertiary industry is the inevitable result of the improvement of productivity and social progress. The level of tertiary industry is an important symbol to measure the degree of economic development of modern society.