We put forward a new idea about land appraisal-opportunity cost technique,which based on the conception of opportunity in microeconomics.

Discusion on the credit system in view of opportunity cost;

Study on accounting cost and opportunity cost;

Calculation of economic benefit of ecological environment water supply with opportunity cost method;

Education opportunity costs which remain bigger costs for students and their families deserve the attention from theorists,students and the families.

As a component part of the government,police organization is typical hierarchical structure and there is lots of principal agent relationship in it which may bring lower management efficiency that is caused by the asymmetric information,opportunity costs and regulations failure.

The economy rent is a kind of the surplus in which the benefit obtained by the owner of production factor exceeds the opportunity cost of the production factor.

Noting that colleges and universities should attach importance to the library readers the opportunity cost and the time value of the current University Library.

The capability costs of power plant are calculated using accountant cost method,and the time-of-use capability price is determined according to the abundant degree of powe.