Engineering economics is an interdisciplinary subject between engineering and economics, and it is a subject that studies the economic effects of engineering technology practice activities. That is, with engineering projects as the main body and technology-economic system as the core, how to effectively use resources and improve economic benefits is studied. Engineering economics studies the economic benefits of various engineering technical schemes, and studies how to obtain the expected output with minimum input or how to obtain the maximum output with the same input in the process of using various technologies; How to realize the necessary functions of products, operations and services at the lowest life cycle cost. Engineering Economics: To learn the concept of engineering economics, we must first understand the concepts of engineering and economics, which is helpful to understand the concept of engineering economics. Engineering generally refers to the general name of various disciplines formed by applying the principles of natural science to industrial and agricultural production. These disciplines are developed by applying basic scientific principles such as mathematics, physics and chemistry, combined with technical experience accumulated in production practice, such as chemical engineering, metallurgy, electromechanical engineering, civil engineering, water conservancy, transportation, textile and food engineering. The main contents include the design and formulation of production technology; Design and manufacture of production equipment, design and manufacture of testing principle and equipment, research and selection of raw materials, survey design and construction design of civil engineering, construction of civil engineering, etc. In addition, it is customary to refer to a specific project as a project for short, such as the Three Gorges Hydropower Project, the Qinghai-Tibet Railway Project, the Beijing Olympic Stadium Construction Project, the large-scale oil refining project, the 50-ton ethylene project, the nuclear power plant project, the expressway construction project, the urban water supply plant or sewage treatment plant project, the enterprise technical transformation and expansion project, and the new product development project, new drug research project, software development project, new technology and new equipment in production and business activities. Engineering in engineering economics includes not only engineering technical schemes and technical measures, but also engineering projects.

All the above-mentioned projects (no matter what type or project) have a common feature, that is, they are all means for human beings to use and transform nature, and they are also ways and means for people to create huge material wealth. Their fundamental purpose is to serve the better life of all mankind.

The concept of economy has four meanings: first, social relations of production, which refers to the socio-economic system in which human society has developed to a certain stage. It is the sum total of social relations of production and the foundation of the political and ideological superstructure. Second, it refers to the floorboard of the national economy, such as the floorboard of a country's social and industrial sectors (primary industry: agriculture and extractive industries; Secondary industry: processing and manufacturing; Tertiary industry: service industry). Third, it refers to human economic activities, that is, the production, exchange, distribution and consumption of material materials. Fourth, it refers to saving or saving, that is, saving in people's daily work and life, including both the rational use and saving of social resources and the saving of personal family living expenses. Engineering economics mainly applies the meaning of economy in economics.

Engineering economics is a systematic theory and method for economic analysis of engineering technical problems. Engineering economics is a science that uses the analysis method of engineering economics to analyze and compare various feasible schemes of engineering technology (project) and select and determine the best scheme under the condition of limited resources. Its core task is to make economic decision on the technical scheme of the project.